Exhibit 32.1

CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the accompanying Annual Report of A. M. Castle & Co. (the “Company”) on Form 10-K for the period ended December 31, 2005 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, G. Thomas McKane, Chairman of the Board of the Company, certify to the best of my knowledge, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

(1)	The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and
(2)	The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ G. Thomas McKane

G. Thomas McKane

Chairman of the Board

March 28, 2006

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