EXHIBIT 5.1


                                                              October 4, 2005

Cytec Industries Inc.,
  Five Garret Mountain Plaza,
    West Paterson, New Jersey  07424.

Ladies and Gentlemen:

         In connection with the registration under the Securities Act of 1933,
as amended (the "Act"), and issuance by you of (i) $250,000,000 principal amount
of 5.5% Notes due 2010 (the "2010 Notes") and (ii) $250,000,000 principal amount
of 6.0% Notes due 2015 (the "2015 Notes" and, together with the 2010 Notes, the
"Securities") pursuant to the Indenture, dated as of March 15, 1998, as amended
by the First Supplemental Indenture, dated as of May 11, 1998 (the "Indenture"),
between Cytec Industries Inc. (the "Company") and JPMorgan Chase Bank, National
Association, as successor to PNC Bank, National Association, as Trustee (the
"Trustee"), we, as your special counsel, have examined such corporate records,
certificates and other documents, and such questions of law, as we have
considered necessary or appropriate for the purposes of this opinion.

         Upon the basis of such examination, we advise you that, in our opinion,
the Securities constitute valid and legally binding obligations of the Company




Cytec Industries Inc.,                                                       -2-


enforceable in accordance with their terms, subject to bankruptcy, insolvency,
fraudulent transfer, reorganization, moratorium and similar laws of general
applicability relating to or affecting creditors' rights and to general equity
principles.

         As contemplated by the qualifications set forth above, in rendering the
foregoing opinion, we are expressing no opinion as to Federal or state laws
relating to fraudulent transfers.

         The foregoing opinion is limited to the Federal laws of the United
States and the laws of the State of New York, and we are expressing no opinion
as to the effect of the laws of any other jurisdiction.

         We have relied as to certain matters on information obtained from
public officials, officers of the Company and other sources believed by us to be
responsible, and we have assumed that the Indenture has been duly authorized,
executed and delivered by the Trustee, that the Securities conform to the
specimens thereof examined by us, that the Trustee's certificates of
authentication of the Securities have been manually signed by one of the
Trustee's authorized officers, and that the signatures on all documents examined
by us are genuine, assumptions which we have not independently verified.

         We hereby consent to the filing of this opinion as an exhibit to a
Current Report on Form 8-K filed by the Company for purposes of incorporating
this opinion into the registration statement relating to the Securities and to
the references to us under the heading "Validity of Notes" in the Prospectus
Supplement relating to the Securities. In




Cytec Industries Inc.,                                                       -3-


giving such consent, we do not thereby admit that we are in the category of
persons whose consent is required under Section 7 of the Act.

                                                  Very truly yours,

                                                  /s/ Sullivan & Cromwell LLP