National Fuel Gas Company Form 11-K for December 31, 2005

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

F O R M 11-K

ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE
SECURITIES EXCHANGE ACT OF 1934

For the Year Ended December 31, 2005


NATIONAL FUEL GAS COMPANY
TAX-DEFERRED SAVINGS PLAN
(Full title of the Plan)


NATIONAL FUEL GAS COMPANY
(Name of issuer of the securities held pursuant to the Plan)

6363 Main Street, Williamsville, New York 14221
(Address of principal executive office)




1


REQUIRED INFORMATION

  1. Plan financial statements and schedules prepared in accordance with financial reporting requirements of ERISA.

    See accompanying Index on page 3.

  2. Signature

  3. Exhibit
  Exhibit Number Description of Exhibit
          23 Independent Registered Public Accounting Firm's Consent



2


NATIONAL FUEL GAS COMPANY

TAX-DEFERRED SAVINGS PLAN

INDEX TO FINANCIAL STATEMENTS AND SCHEDULE

                                                                                                Page
                                                                                               Number
                                                                                               ------

Report of Independent Registered Public Accounting Firm                                           1

Financial Statements:

  Statement of Net Assets Available for
  Benefits at December 31, 2005                                                                   2

  Statement of Net Assets Available for
  Benefits at December 31, 2004                                                                   3

  Statements of Changes in Net Assets
  Available for Benefits for the Year Ended
  December 31, 2005 (with Comparative
  Totals for the Year Ended December 31, 2004)                                                    4

Notes to Financial Statements                                                                   5 - 8

Supplemental Schedule:

  Schedule of Assets (Held at End of Year)
       as of December 31, 2005                                                                    9


3


Report of Independent Registered Public Accounting Firm

To the Participants and
Plan Administrator of the
National Fuel Gas Company
Tax-Deferred Savings Plan

We have audited the accompanying statements of net assets available for benefits of the National Fuel Gas Company Tax-Deferred Savings Plan as of December 31, 2005 and 2004, and the related statements of changes in net assets available for benefits for the years then ended. These financial statements are the responsibility of the Plan’s management. Our responsibility is to express an opinion on these financial statements based on our audits.

We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Plan's internal control over financial reporting. Accordingly, we express no opinion. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in all material respects, the net assets available for benefits of the National Fuel Gas Company Tax-Deferred Savings Plan as of December 31, 2005 and 2004, and the changes in net assets available for benefits for the years then ended in conformity with U. S. generally accepted accounting principles.

Our audits were performed for the purpose of forming an opinion on the basic financial statements taken as a whole. The supplemental schedule is presented for the purpose of additional analysis and is not a required part of the basic financial statements, but is supplementary information required by the Department of Labor’s Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974. This supplemental schedule is the responsibility of the Plan’s management. The supplemental schedule has been subjected to the auditing procedures applied in the audit of the basic financial statements for the year ended December 31, 2005 and, in our opinion, is fairly stated in all material respects in relation to the basic financial statements taken as a whole.

                                                            FREED MAXICK & BATTAGLIA, CPAs, P.C.

May 18, 2006
Buffalo, New York

4


NATIONAL FUEL GAS COMPANY

TAX-DEFERRED SAVINGS PLAN

STATEMENT OF NET ASSETS AVAILABLE FOR BENEFITS

DECEMBER 31, 2005

                                             Employer            Participant              Total
                                             Directed              Directed           December 31,
                                            Investments          Investments              2005
                                       ---------------------- ------------------- ----------------------

Investments at fair value:

   National Fuel Gas Company Common
     Stock Funds                                 $26,417,457         $23,391,349       $49,808,806

   Vanguard 500 Index Fund                                 -          31,824,629        31,824,629

   Vanguard Retirement Savings Trust
                                                           -          12,448,815        12,448,815

   Vanguard Total Bond Market Index
     Fund                                                  -           9,836,107         9,836,107

   Vanguard European Stock Index Fund
                                                           -           3,926,051         3,926,051

   Vanguard Extended Market Index
     Fund                                                  -           3,318,330         3,318,330

   Vanguard Prime Money Market Fund
                                                           -           3,301,030         3,301,030

   Vanguard STAR Fund                                      -           1,968,548         1,968,548

   Vanguard Pacific Stock Index Fund
                                                           -           1,485,052         1,485,052

   Participant Loan Account                                -           2,548,635         2,548,635
                                       ---------------------- ------------------- -----------------

                                                  26,417,457          94,048,546       120,466,003

Receivables:
   Employer Contributions                            127,767               1,789           129,556

   Participant Contributions                               -             513,233           513,233
                                       ---------------------- ------------------- -----------------

Net Assets Available for Plan
Benefits                                         $26,545,224         $94,563,568      $121,108,792
                                       ====================== =================== =================

The accompanying notes are an integral part of these financial statements

5


NATIONAL FUEL GAS COMPANY

TAX-DEFERRED SAVINGS PLAN

STATEMENT OF NET ASSETS AVAILABLE FOR BENEFITS

DECEMBER 31, 2004

                                             Employer            Participant              Total
                                             Directed              Directed           December 31,
                                            Investments          Investments              2004
                                       ---------------------- ------------------- ----------------------

Investments at fair value:

   National Fuel Gas Company Common
     Stock Funds                                 $23,424,895         $20,966,856            $44,391,751

   Vanguard 500 Index Fund                                 -          32,408,674             32,408,674

   Vanguard Retirement Savings Trust
                                                           -          11,966,359             11,966,359

   Vanguard Total Bond Market Index
     Fund                                                  -           9,661,994              9,661,994

   Vanguard European Stock Index Fund
                                                           -           3,633,468              3,633,468

   Vanguard Prime Money Market Fund
                                                           -           3,257,284              3,257,284

   Vanguard Extended Market Index
     Fund                                                  -           3,069,415              3,069,415

   Vanguard Pacific Stock Index Fund
                                                           -           1,041,191              1,041,191

   Vanguard STAR Fund                                      -             902,747                902,747

   Participant Loan Account                                -           2,626,113              2,626,113
                                       ---------------------- ------------------- --- ------------------

                                                  23,424,895          89,534,101            112,958,996

Receivables:
   Employer Contributions                            143,631                   -                143,631

   Participant Contributions                               -             552,352                552,352
                                       ---------------------- ------------------- --- ------------------

Net Assets Available for Plan
Benefits                                         $23,568,526         $90,086,453           $113,654,979
                                       ====================== =================== === ==================

The accompanying notes are an integral part of these financial statements

6


NATIONAL FUEL GAS COMPANY

TAX-DEFERRED SAVINGS PLAN

STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS

FOR THE YEAR ENDED DECEMBER 31, 2005

(WITH COMPARATIVE TOTALS FOR THE YEAR ENDED DECEMBER 31, 2004)

                                                                                     Total all Investments Combined
                                             Employer            Participant      --------------------------------------
                                             Directed              Directed                   December 31,
                                            Investments          Investments            2005               2004
                                       ---------------------- ------------------- ----------------- --------------------
Investment Income From National Fuel
Gas Company Common Stock Funds
                                                   $933,060            $823,611        $1,756,671           $1,681,794

Interest and Dividend Income                              -             627,822           627,822              604,634

Investment Income from Mutual Funds
                                                          -           1,278,662         1,278,662            1,175,551
                                       ---------------------- ------------------- ----------------- --------------------

     Total Investment Income                        933,060           2,730,095         3,663,155            3,461,979

Net Appreciation  in Fair Value
of Investments                                    2,398,744           3,642,438         6,041,182            9,778,185

Employer Contributions                            1,423,835              12,967         1,436,802            1,533,438

Participant Contributions                                 -           5,783,419         5,783,419            6,123,169

Participant Purchase and Loan Fees
                                                     (1,658)             (3,682)           (5,340)              (5,714)

Rollovers and Other Individual
Transfers Out                                      (134,128)           (439,309)         (573,437)            (304,304)

Payments to Participants or
Beneficiaries                                    (1,643,188)         (7,248,780)       (8,891,968)          (8,585,027)

Transfers (To)/From Associated Funds
                                                         33                 (33)                -                    -
                                       ---------------------- ------------------- ----------------- --------------------

Increase In Net Assets Available for
Plan Benefits                                     2,976,698           4,477,115         7,453,813           12,001,726

Net Assets Available for Plan
Benefits:
     Beginning of Year                           23,568,526          90,086,453       113,654,979          101,653,253
                                       ---------------------- ------------------- ----------------- --------------------

     End of Year                                $26,545,224         $94,563,568      $121,108,792         $113,654,979
                                       ====================== =================== ================= ====================

The accompanying notes are an integral part of these financial statements

7


NATIONAL FUEL GAS COMPANY

TAX-DEFERRED SAVINGS PLAN

NOTES TO FINANCIAL STATEMENTS

NOTE 1 – DESCRIPTION OF PLAN

      General:

        The following is a brief description of the National Fuel Gas Company Tax-Deferred Savings Plan (the Plan) provided for general information purposes only. Participants should refer to the Plan document for more complete information. The Plan is a defined contribution plan as permitted under Section 401(k) of the Internal Revenue Code. The Plan was adopted March 21, 1989, effective as of July 1, 1989, and has been amended since that time. It is subject to the Employee Retirement Income Security Act of 1974, as amended.

        During 2003, the Board of Directors of the Company approved the merger of the National Fuel Gas Company Employees’ Thrift Plan (the “Thrift Plan”) into the Plan, in part, and into another plan, in part. Specifically, the account balances contained in the Thrift Plan’s Government Bond Fund and the Pooled Investment Contract Fund were merged into the Plan. The account balances containing the employer directed investment fund of the Thrift Plan, which consisted of National Fuel Gas Company Common Stock, was merged into another plan. The merger was effective as of August 1, 2003. Funds previously invested in the Government Bond Fund were initially invested in the Vanguard Total Bond Market Index Fund, and funds previously invested in the Pooled Investment Contract Fund were initially invested in the Vanguard Retirement Savings Trust. Former Thrift Plan participants have the option to move these funds into other investment options offered by the Plan and retain the same rights and features of the former Thrift Plan. Former Thrift Plan funds are kept separate from any funds that a participant invests directly into the Plan.

        As of January 1, 2004, an additional Retirement Savings Account benefit was provided to certain participants in the Plan. Participants should refer to the Plan document for more complete information.

      Eligibility and Participation:

        Originally, the Plan was established for the benefit of employees of National Fuel Gas Company and its subsidiaries (the Company) who were subject to a collective bargaining agreement between the Company and the International Brotherhood of Electrical Workers (IBEW), Locals 2154 and 2199 (which consolidated with 2199-J). These employees became eligible to participate in the Plan on July 1, 1989 or, if later, after completing 1,000 hours of service and attaining age 21. Employees subject to collective bargaining agreements between the Company and the IBEW Local 2279 (now consolidated with IBEW Local 2154) and the Service Employee International Union (SEIU) F & O Conference — Local 22 (prior to their consolidation on September 1, 1999, the International Brotherhood of Firemen and Oilers, Locals 22, 23, 25 and 251) also became eligible to participate in the Plan on August 1, 1990 or, if later, after completing 1,000 hours of service and attaining age 21. Eligible Plan participants for the Retirement Savings Account Benefit will have completed 12 months of employment, including at least 1,000 hours of service, attained age 21 and whose first hour of service with the Company is credited on or after November 1, 2003.

      Contributions:

        Plan participants may direct the Company to reduce their base pay by a specified full percentage of at least 2% and not more than 50%. These wage reductions are subject to certain Plan and Internal Revenue Code limitations, and the Company remits them to the Plan Trustee on the participants’ behalf. In addition, the Company makes an employer matching contribution that ranges from 1% to 3.5% of the participants’ base pay depending upon their years of service and rate of wage reduction contributions. Participants may also contribute amounts representing distributions from other qualified defined benefit or defined contribution plans. Participants direct the investment of their contributions into various investment

8


options offered by the Plan. Participants may change their investment allocation on a daily basis. Beginning January 2004, the participants eligible for the Retirement Savings Account Benefit will receive a Company contribution of 2% or 3% of the participant’s compensation, depending on the participant’s years of service. The Company contribution in the Retirement Savings Account is participant directed and can be directed into any of the Plan’s investment options except for the Common Stock of National Fuel Gas Company.

        “Base pay” is defined in the Plan as a participant’s basic compensation for a payroll period. An individual participant’s wage reduction contributions to the Plan are subject to ceilings imposed by the Internal Revenue Service. However, Company matching contributions are not subject to such ceilings. The ceiling is $14,000 for 2005 and $15,000 for 2006. If a participant is age 50 or over, the ceiling increases to $18,000 for 2005 and $20,000 for 2006.

        Participants’ accounts, including all wage reduction contributions, employer matching contributions, and the earnings thereon, are at all times fully vested and nonforfeitable. Participant’s accounts within the Retirement Savings Account are 100% vested following five years of service. Forfeitures will be used to reduce Company contributions. There are no forfeitures for the years ending December 31, 2005 and 2004.

      Employer Matching Contributions:

        Employer matching contributions are invested in a fund consisting primarily of the common stock of National Fuel Gas Company (National Fuel Gas Company Stock Fund B). This fund also maintains a small cash position in Vanguard Prime Money Market Fund and may also include receivables and/or payables for unsettled security transactions and receivables for accrued dividends. A separate account is maintained for each participant showing his/her interest in this fund. Participants may not redirect their interests in this fund into any other fund.

      Withdrawals, Loans and Distributions:

        Plan participants (or their beneficiaries) may receive distributions from the Plan upon death, retirement, disability or other termination, in accordance with a qualified domestic relations order, or in the event of hardship, subject to the Plan’s limitations and restrictions. Additionally, Plan participants may borrow from their accounts in accordance with various Plan rules. In certain cases, participants may postpone receipt of Plan distributions.

        Former Thrift Plan Participants may, at any time, withdraw the entire value of those amounts transferred to the Plan.

      Participant Accounts:

        Each participant’s account is credited with the participant’s contribution and an allocation of (a) the Company’s contribution and, (b) Plan earnings, and charged with an allocation of investment fees. Allocations are based on participant earnings or account balances, as defined. The benefit to which a participant is entitled is the benefit that can be provided from the participant’s account.

      Administration:

        National Fuel Gas Company is the Administrator of the Plan. A Tax-Deferred Savings Plan Committee appointed by National Fuel Gas Company’s Board of Directors exercises National Fuel Gas Company’s duties as Administrator. The assets of the Plan are held by the Trustee, Vanguard Fiduciary Trust Company (Vanguard).

      Plan Termination:

        Although it has not expressed any intent to do so, National Fuel Gas Company has the right to terminate, amend, or modify the Plan at any time subject to the provisions of ERISA.

9


NOTE 2 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

      Basis of Accounting:

        The accounts of the Plan are maintained on the accrual basis.

      Investment Valuation and Income Recognition:

        National Fuel Gas Company Stock Funds A (participant directed) and B (non-participant directed) are reported on a current value basis using the quoted market value of National Fuel Gas Company common stock and the value of the cash positions and receivables at the close of the Plan year. Shareholders of National Fuel Gas Company stock have the right to give voting instructions to the Trustee with respect to the number of shares of common stock of National Fuel Gas Company that are held on their behalf. Mutual funds are reported on a current value basis, using quoted market values of the investments at the close of the Plan year. The investment contracts in the Vanguard Retirement Savings Trust are carried at the stated unit values of the funds which are derived from the fair value of the underlying investments. Participant loans are valued at their outstanding balances, which approximate fair value. National Fuel Gas Company stock distributed to participants is reflected at market value at the date of distribution. Purchases and sales of investments are recorded on a trade-date basis. Interest income is accrued when earned. Dividend income is recorded on the ex-dividend date. Capital gain distributions are included in investment income.

      Risks and Uncertainties:

        The Plan invests in various investment securities. Investment securities are exposed to various risks such as interest rate, market and credit risks. Due to the level of risk associated with certain investment securities, it is at least reasonably possible that changes in the values of investment securities will occur in the near term and that such changes could materially affect participants’ account balances and the amounts reported in the statement of net assets available for plan benefits.

      Use of Estimates:

        The preparation of financial statements in conformity with U. S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and changes therein, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of additions and deductions during the reporting period. Actual results could differ from those estimates.

      Administrative Expenses:

        Expenses related to administration of the Plan and Trust are borne by the Company. The Company paid Vanguard $44,078 and $43,700, for services in connection with the Plan and Trust for the years ended December 31, 2005 and December 31, 2004, respectively. Brokerage commissions and similar costs of acquiring or selling securities (if any) that are incurred by the investment funds are borne by the participant. Loan origination fees and annual maintenance fees for each loan are also borne by the participant.

      Payments of Benefits:

        Benefits payments to participants are recorded upon distribution.

      Recent Accounting Pronouncements:

        In December 2005, the Financial Accounting Standards Board (FASB) issued FASB Staff Position (FSP) AAG INV-1 & SOP 94-4-1, "Reporting of Fully Benefit-Responsive Investment Contracts Held by Certain Investment Companies Subject to the AICPA Investment Company Guide and Defined - Contribution Health and Welfare and Pension Plans". The FSP addresses the application of contract value accounting for benefit-responsive investment contracts owned by certain stable-value commingled pools, such as a Trust. While the FSP permits the continued use of contract value accounting to determine the net asset of the Trust, it will require several changes in financial statement presentation and

10


disclosure, including presentation of both the fair value and contract value for benefit-responsive investment contracts. The FSP will be effective for years ending after December 15, 2006. If comparative financial statements are presented, the guidance in that FSP shall be applied retroactively to all prior periods presented. Management has not yet determined the impact on the financial statements of the Plan.

NOTE 3 – INCOME TAXES

        The Internal Revenue Service has determined in a letter dated September 9, 2002 that the Plan qualifies under Section 401(a) and Section 401(k) of the Internal Revenue Code of 1986, as amended. Accordingly, no provision for income taxes has been recorded. Although the Plan has been amended since receiving the determination letter, the Plan administrator and the Plan’s tax counsel believe that the Plan is designed and is currently being operated in compliance with the applicable requirements of the Internal Revenue Code.

NOTE 4 – PARTIES-IN-INTEREST

        The Plan invests in shares of mutual funds managed by an affiliate of Vanguard Fiduciary Trust Company (VFTC). VFTC acts as trustee for only those investments as defined by the Plan. The Plan also invests in common stock of National Fuel Gas Company. Transactions in such investments qualify as party-in-interest transactions which are exempt from the prohibited transaction rules. Investment income from parties-in-interest amounted to $3,663,155 and $3,461,979 for the years ended December 31, 2005 and December 31, 2004, respectively.

NOTE 5 – INVESTMENTS

        The following investments comprised more than 5% of Plan assets:

                                                                         December 31,
                                                                         ------------
                                                                     2005             2004
                                                                     ----             ----

         National Fuel Gas Company Common
                  Stock Fund A (Participant Directed)           $23,391,349       $20,966,856
         National Fuel Gas Company Common
                  Stock Fund B (Non-Participant Directed)        26,417,457        23,424,895
         Vanguard 500 Index Fund                                 31,824,629        32,408,674
         Vanguard Retirement Savings Trust                       12,448,815        11,966,359
         Vanguard Total Bond Market Index Fund                    9,836,107         9,661,994

         The net appreciation (depreciation) in fair value of investments are as follows:

                                                                      For the Years Ended
                                                                          December 31,
                                                                      -------------------
                                                                     2005             2004
                                                                     ----             ----

         National Fuel Gas Company Common
                  Stock Fund A (Participant Directed)             $2,122,813          $2,902,467
         National Fuel Gas Company Common
                  Stock Fund B (Non-Participant Directed)          2,398,744           3,158,063
         Vanguard 500 Index Fund                                     904,876           2,585,372
         Vanguard Extended Market Index Fund                         286,262             434,883
         Vanguard Pacific Stock Index Fund                           235,420             149,971
         Vanguard European Stock Index Fund                          235,391             541,461
         Vanguard STAR Fund                                           64,137              40,930
         Vanguard Total Bond Market Index Fund                      (206,461)            (34,962)
                                                                   ----------          ----------
                                                                  $6,041,182          $9,778,185
                                                                   ==========          ==========


11


SCHEDULE I

NATIONAL FUEL GAS COMPANY

TAX-DEFERRED SAVINGS PLAN

SCHEDULE OF ASSETS (HELD AT END OF YEAR)

DECEMBER 31, 2005

                                            (c) Description of Investment
        (b) Identity of Issue,                   Including Maturity Date, Rate
             Borrower, Lessor                    of Interest, Collateral, Par                                (e) Current
(a)          or Similar Party                    or Maturity Value                            (d) Cost            Value
---     ----------------------               ----------------------------------               --------       -----------

*       National Fuel Gas Company
         Common Stock Funds:
           National Fuel Gas Company        Stock Fund A (1,048,939 units)                                     $23,391,349
           National Fuel Gas Company        Stock Fund B (1,184,639 units)                   $ 18,754,424       26,417,457
                                                                                                                ----------
                                            Total National Fuel Gas Company
                                              Common Stock Funds                                                49,808,806
                                                                                                                ----------

        Mutual Funds:
*          Vanguard Group of                500 Index Fund
             Investment Companies             (276,928 units)                                                   31,824,629

*          Vanguard Group of                Total Bond Market Index Fund
             Investment Companies             (977,744 units)                                                    9,836,107

*          Vanguard Group of                European Stock Index Fund
             Investment Companies             (141,735 units)                                                    3,926,051

*          Vanguard Group of                Extended Market Index Fund
             Investment Companies             (96,857 units)                                                     3,318,330

*          Vanguard Group of                Prime Money Market Fund
             Investment Companies             (3,301,030 units)                                                  3,301,030

*           Vanguard Group of               STAR Fund
               Investment Companies           (100,436 units)                                                    1,968,548

*          Vanguard Group of                Pacific Stock Index Funds
             Investment Companies             (130,957 units)                                                    1,485,052
                                                                                                                ----------

                                            Total Vanguard Mutual Funds                                         55,659,747
                                                                                                                ----------

        Common/Collective Trust (1):
*          Vanguard Group of                Retirement Savings Trust
             Investment Companies             (12,448,815 units)                                                12,448,815

*       National Fuel Gas Company
           Tax-Deferred Savings Plan        Participant Loan Account                                             2,548,635
                                                                                                               -----------

                                                  TOTAL                                                       $120,466,003
                                                                                                               ===========

*     Denotes known party-in-interest to the Plan.


(1)   The audited annual report for the Vanguard Retirement Savings Trust has been filed with the Department of Labor by the Vanguard
      Fiduciary Trust Company. The entity's tax identification number is 23-2186884.

12



SIGNATURE

The Plan. Pursuant to the requirements of the Securities Exchange Act of 1934, the trustees (or other persons who administer the employee benefit plan) have duly caused this annual report to be signed on its behalf by the undersigned hereunto duly authorized.

  NATIONAL FUEL GAS COMPANY
  TAX DEFERRED SAVINGS PLAN
          (Name of Plan)
   
   
   
  By /s/ R. J. Tanski
  R. J. Tanski
  Treasurer and Principal Financial Officer
   
   
   
  By /s/ K. M. Camiolo
  K. M. Camiolo
  Controller and Principal Accounting Officer
   
Date: June 28, 2006

13


EXHIBIT INDEX

Exhibit Number Description of Exhibit
        23 Independent Registered Public Accounting Firm's Consent

14