Exhibit 5.1

                        Jerry M. Aufox, Corporate Counsel
                               A. M. Castle & Co.
                              3400 North Wolf Road
                          Franklin Park, Illinois 60131


A. M. Castle & Co.
3400 North Wolf Road
Franklin Park, Illinois 60131

         Re:      Registration Statement on Form S-3 of
                  A. M. Castle & Co. (the "Registration Statement")

Gentlemen and Ladies:

     I am Secretary and Corporate Counsel of A. M. Castle & Co. In connection
with the proposed registration for resale of up to 700,000 shares of common
stock, par value $0.01 per share (the "common stock "), of A. M. Castle & Co.
(the "Company"), covered by the Registration Statement, I have examined such
documents and have reviewed such questions of law as I have considered necessary
and appropriate for the purposes of this opinion. I have assumed the genuineness
of all signatures, the authenticity of all documents submitted to as originals,
the conformity to original documents of all the documents submitted to me as
certified or photostatic copies and the authenticity of the originals of such
latter documents.

     Based upon such examination, I advise you that, in my opinion, the shares
of common stock registered for resale as set forth in the Registration Statement
have been duly authorized and were validly issued and fully paid and
nonassessable, and will continue to be so when sold as set forth in the
Registration Statement.

     I hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and the reference to this firm under the caption
"Validity of Stock"' in the prospectus constituting a part of such Registration
Statement. In giving this consent, I do not hereby admit that I am in the
category of persons whose consent is required under Section 7 of the Securities
Act of 1933 or the rules and regulations of the Securities and Exchange
Commission.

                                            Very truly yours,

                                            /s/  JERRY M. AUFOX
                                            -----------------------------
                                                 Jerry M. Aufox, Secretary and
                                                 Corporate Counsel