Exhibit 5.1


                           Kirkpatrick & Lockhart LLP
                            Henry W. Oliver Building
                              535 Smithfield Street
                            Pittsburgh, PA 15222-2312



                                  July 22, 2004

Allegheny Technologies Incorporated
1000 Six PPG Place
Pittsburgh, PA 15222

Ladies and Gentlemen:

      We have acted as your counsel in connection with the sale by Allegheny
Technologies Incorporated (the "Company") of up to 13,800,000 shares (the
"Shares") of Common Stock, par value $0.10 per share ("Common Stock"), of the
Company, including 1,800,000 shares of Common Stock for which the underwriters
have been granted an over-allotment option (the "Option Shares"), pursuant to
the Registration Statement on Form S-3 (File No. 333-113820) (the "Registration
Statement") filed with the Securities and Exchange Commission under the
Securities Act of 1933 (the "Securities Act"), the related Prospectus, dated May
26, 2004 (the "Prospectus"), contained therein and the related Prospectus
Supplement, dated July 22, 2004 (the "Prospectus Supplement").

      You have requested our opinion as to the matters set forth below in
connection with the sale by the Company of the Shares. For purposes of rendering
that opinion, we have examined the Registration Statement, the Prospectus, the
Prospectus Supplement, the Company's Restated Certificate of Incorporation and
Bylaws and the corporate action of the Company that provides for the issuance of
the Shares, and we have made such other investigation as we have deemed
appropriate. We have examined and relied upon certificates of public officials.

      Our opinion set forth below is limited to the Delaware General Corporation
Law, including the applicable provisions of the Delaware Constitution and
reported judicial decisions interpreting those laws.

      Based upon and subject to the foregoing, it is our opinion that the Shares
are duly authorized for issuance by the Company and, when issued and paid for as
described in the Prospectus and the Prospectus Supplement, will be validly
issued, fully paid and nonassessable.

      We hereby consent to the filing of this opinion as an exhibit to the
Company's Current Report on Form 8-K filed on the date hereof, the incorporation
by reference of this opinion into the Registration Statement, the Prospectus and
the Prospectus Supplement and the reference to this firm under the caption
"Legal Matters" in the Prospectus and the Prospectus Supplement. In giving our
consent we do not thereby admit that we are in the category of persons whose
consent is required under Section 7 of the Securities Act or the rules and
regulations thereunder.

                                          Yours truly,
                                          /s/ KIRKPATRICK & LOCKHART LLP