EXHIBIT 5

                                                    March 28, 2002



ESCO Technologies Inc.
8888 Ladue Road, Suite 200
St. Louis, MO  63124

Ladies and Gentlemen:

     I am Assistant Secretary and Assistant General Counsel of ESCO Technologies
Inc., a Missouri corporation (the "Company"), and in such capacity I am familiar
with the Registration Statement on Form S-8 (the "Registration Statement")
relating to the Company's 2001 Stock Incentive Plan (the "Plan") to which this
letter is filed as an exhibit. The Registration Statement registers 1,105,365
shares of the Company's common stock, par value $0.01 per share (the "Common
Stock"), offered pursuant to stock options, stock appreciation rights,
performance share awards and other stock-based awards, granted and which may be
granted under the Plan, including the Preferred Stock Purchase Rights associated
with such Common Stock (the Common Stock and its associated Preferred Stock
Purchase Rights, the "Securities").

     I have examined originals or copies, certified or otherwise identified to
my satisfaction, of such documents, corporate records, certificates of public
officials and other instruments as I deemed necessary for the purpose of the
opinion expressed herein.

     On the basis of the foregoing, I am of the opinion that the Securities,
when sold in accordance with the provisions of the Plan, will be legally issued,
fully paid and non-assessable.

     I consent to the filing of this letter as an exhibit to the Registration
Statement.

                                                    Very truly yours,


                                                    /s/ Thomas B. Martin
                                                    ----------------------------
                                                    Thomas B. Martin

TBM/bjo/02-52

Enclosures