UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
(Amendment No. 3)*
ESCO TECHNOLOGIES INC
(Name of Issuer)
COMMON STOCK
(Title of Class of Securities)
296315104
(CUSIP Number)
December 31, 2008
(Date of Event which Requires Filing of Statement)
Check the appropriate box to designate the Rule pursuant to which
this Schedule is filed:
[x] Rule 13d - 1(b)
Rule 13d - 1(c)
Rule 13d - 1(d)
*The remainder of this cover page shall be filled out for a
reporting person's initial filing on this form with respect to
the subject class of securities, and for any subsequent amendment
containing information which would alter disclosures provided in
a prior cover page.
The information required on the remainder of this page shall not
be deemed to be "filed" for the purpose of Section 18 of the
Securities Exchange Act of 1934 ("Act") or otherwise subject to
the liabilities of that section of the Act but shall be subject
to all other provisions of the Act (however, see the Notes.)
(Continued on following page(s)
Page 1 of 6 Pages
CUSIP NO. 296315104 13G Page 2 of 6 Pages
1 Name of Reporting Person
S.S. or I.R.S. Identification No. of Above Person
T. ROWE PRICE ASSOCIATES, INC.
52-0556948
2 Check the Appropriate Box if a Member of a Group*
(a) ____
NOT APPLICABLE (b) ____
3 SEC Use Only
______________________________
4 Citizenship or Place of Organization
MARYLAND
Number of 5 Sole Voting Power
**
Shares 190,700
Beneficially 6 Shared Voting Power
**
Owned By Each -0-
Reporting 7 Sole Dispositive Power
**
Person 1,966,040
With 8 Shared Dispositive Power
-0-
9 Aggregate Amount Beneficially Owned by Each Reporting Person
1,966,040
10 Check Box if the Aggregate Amount in Row (9) Excludes Certain
Shares*
NOT APPLICABLE
11 Percent of Class Represented by Amount in Row 9
7.5%
12 Type of Reporting Person*
IA
*SEE INSTRUCTION BEFORE FILLING OUT!
**Any shares reported in Items 5 and 6 are also
reported in Item 7.
CUSIP NO. 296315104 13G Page 3 of 6 Pages
1 Name of Reporting Person
S.S. or I.R.S. Identification No. of Above Person
T. ROWE PRICE SMALL-CAP STOCK FUND, INC.
23-1622210
2 Check the Appropriate Box if a Member of a Group*
(a) ____
NOT APPLICABLE (b) ____
3 SEC Use Only
______________________________
4 Citizenship or Place of Organization
Maryland
Number of 5 Sole Voting Power
**
Shares 1,100,000
Beneficially 6 Shared Voting Power
**
Owned By Each NONE
Reporting 7 Sole Dispositive Power
**
Person NONE
With 8 Shared Dispositive Power
NONE
9 Aggregate Amount Beneficially Owned by Each Reporting Person
1,100,000
10 Check Box if the Aggregate Amount in Row (9) Excludes Certain
Shares*
NOT APPLICABLE
11 Percent of Class Represented by Amount in Row 9
4.2%
12 Type of Reporting Person*
IV
*SEE INSTRUCTION BEFORE FILLING OUT!
**The aggregate amount reported on this page is also included in
the aggregate amount reported by T. Rowe Price Associates, Inc.
on page 2 of this Schedule 13G.
SCHEDULE 13G
PAGE 4 OF 6
Item 1(a) Name of Issuer:
Reference is made to page 1 of this Schedule 13G
Item 1(b) Address of Issuer's Principal Executive Offices:
9900 A Clayton Road, St. Louis, MO 63124
Item 2(a) Name of Person(s) Filing:
(1) T. Rowe Price Associates, Inc. ("Price
Associates")
(2) T. Rowe Price Small-Cap Stock Fund, Inc.
X Attached as Exhibit A is a copy of an agreement between
the Persons Filing (as specified hereinabove) that this
Schedule 13G is being filed on behalf of each of them.
Item 2(b) Address of Principal Business Office:
100 E. Pratt Street, Baltimore, Maryland 21202
Item 2(c) Citizenship or Place of Organization:
(1) Maryland
(2) Maryland
Item 2(d) Title of Class of Securities:
Reference is made to page 1 of this Schedule 13G
Item 2(e) CUSIP Number: 296315104
Item 3 The person filing this Schedule 13G is an:
X Investment Adviser registered under Section 203 of the
Investment Advisers Act of 1940
X Investment Company registered under Section 8 of the
Investment Company Act of 1940
Item 4 Reference is made to Items 5-11 on page 2 of this
Schedule 13G.
SCHEDULE 13G PAGE 5 OF 6
Item 5 Ownership of Five Percent or Less of a Class.
This statement is being filed to report the fact that,
as of the date of this report, T. Rowe Price Small-Cap
Stock Fund has ceased to be the beneficial owner of more
than five percent of the class of securities.
This Item 5 is not applicable with respect to Price
Associates.
Item 6 Ownership of More than Five Percent on Behalf of Another
Person
(1) Price Associates does not serve as custodian of the
assets of any of its clients; accordingly, in each
instance only the client or the client's custodian
or trustee bank has the right to receive dividends
paid with respect to, and proceeds from the sale of,
such securities.
The ultimate power to direct the receipt of
dividends paid with respect to, and the proceeds
from the sale of, such securities, is vested in the
individual and institutional clients which Price
Associates serves as investment adviser. Any and
all discretionary authority which has been delegated
to Price Associates may be revoked in whole or in
part at any time
Except as may be indicated if this is a joint filing
with one of the registered investment companies
sponsored by Price Associates which it also serves
as investment adviser ("T. Rowe Price Funds"), not
more than 5% of the class of such securities is
owned by any one client subject to the investment
advice of Price Associates.
(2) With respect to securities owned by any one of the
T. Rowe Price Funds, only State Street Bank and
Trust Company, as custodian for each of such Funds,
has the right to receive dividends paid with respect
to, and proceeds from the sale of, such securities.
No other person is known to have such right, except
that the shareholders of each such Fund participate
proportionately in any dividends and distributions
so paid.
Item 7 Identification and Classification of the Subsidiary
Which Acquired the Security Being Reported on By the
Parent Holding Company.
Not Applicable.
Item 8 Identification and Classification of Members of the
Group.
Not Applicable.
SCHEDULE 13G
PAGE 6 OF 6
Item 9 Notice of Dissolution of Group.
Not Applicable.
Item 10 Certification.
By signing below I (we) certify that, to the best of my
(our) knowledge and belief, the securities referred to
above were acquired in the ordinary course of business
and were not acquired for the purpose of and do not have
the effect of changing or influencing the control of the
issuer of such securities and were not acquired in
connection with or as a participant in any transaction
having such purpose or effect. T. Rowe Price
Associates, Inc. hereby declares and affirms that the
filing of Schedule 13G shall not be construed as an
admission that Price Associates is the beneficial owner
of the securities referred to, which beneficial
ownership is expressly denied.
Signature.
After reasonable inquiry and to the best of my (our)
knowledge and belief, I (we) certify that the
information set forth in this statement is true,
complete and correct.
Dated: February 13, 2009 Dated: February 13, 2009
T. ROWE PRICE SMALL-CAP STOCK T. ROWE PRICE ASSOCIATES, INC.
FUND, INC.
By: /s/ David Oestreicher By: /s/ David Oestreicher
David Oestreicher, David Oestreicher,
Vice President Vice President
Note: This Schedule 13G, including all exhibits, must be filed
with the Securities and Exchange Commission, and a copy
hereof must be sent to the issuer by registered or
certified mail not later than February 14th following
the calendar year covered by the statement or within the
time specified in Rule 13d-1(b)(2), if applicable.
12/31/2008
EXHIBIT A
AGREEMENT
JOINT FILING OF SCHEDULE 13G
T. Rowe Price Associates, Inc. (an investment adviser
registered under the Investment Advisers Act of 1940) and T. Rowe
Price Small-Cap Stock Fund, Inc., a Maryland corporation, hereby
agree to file jointly the statement on Schedule 13G to which this
Agreement is attached, and any amendments thereto which may be
deemed necessary, pursuant to Regulation 13D-G under the
Securities Exchange Act of 1934.
It is understood and agreed that each of the parties hereto
is responsible for the timely filing of such statement and any
amendments thereto, and for the completeness and accuracy of the
information concerning such party contained therein, but such
party is not responsible for the completeness or accuracy of
information concerning the other party unless such party knows or
has reason to believe that such information is inaccurate.
It is understood and agreed that a copy of this Agreement
shall be attached as an exhibit to the statement on Schedule 13G,
and any amendments hereto, filed on behalf of each of the parties
hereto.
Dated: February 13, 2009 Dated: February 13, 2009
T. ROWE PRICE SMALL-CAP STOCK T. ROWE PRICE ASSOCIATES, INC.
FUND, INC.
By: /s/ David Oestreicher By: /s/ David Oestreicher
David Oestreicher, David Oestreicher,
Vice President Vice President