[LATHAM & WATKINS LETTERHEAD]

Exhibit 5.1

December 5, 2003

United Defense Industries, Inc.
1525 Wilson Boulevard
Suite 700
Arlington, VA 22209

Re:	Registration Statement on Form S-3 (Registration No. 333- ______);
	12,000,000 Shares of Common Stock, par value $.01 per share

Ladies and Gentlemen:

     In connection with the registration by United Defense Industries, Inc., a Delaware corporation (the “Company”), of 12,000,000 shares of common stock, par value $.01 per share (the “Shares”), under the Securities Act of 1933, as amended, on Form S-3 filed with the Securities and Exchange Commission on December 5, 2003 (File No. 333-______), (the “Registration Statement”), you have requested our opinion with respect to the matters set forth below.

     In our capacity as your counsel in connection with such registration, we are familiar with the proceedings taken by the Company in connection with the authorization, issuance and sale of the Shares. In addition, we have made such legal and factual examinations and inquiries, including an examination of originals or copies certified or otherwise identified to our satisfaction of such documents, corporate records and instruments, as we have deemed necessary or appropriate for purposes of this opinion.

     In our examination, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, and the conformity to authentic original documents of all documents submitted to us as copies.

     We are opining herein as to the effect on the subject transaction only of the General Corporation Law of the State of Delaware, and we express no opinion with respect to the applicability thereto, or the effect thereon, of the laws of any other jurisdiction or any other laws or as to any matters of municipal law or the laws of any local agencies within any state.

     Subject to the foregoing, it is our opinion that, as of the date hereof, the Shares have been duly authorized by all necessary corporate action of the Company, are validly issued, fully paid and nonassessable.

United Defense Industries, Inc.
December 5, 2003
Page 2

     We consent to your filing this opinion as an exhibit to the Registration Statement and to the reference to our firm contained under the heading “Legal Matters.”

Very truly yours,

/s/ Latham & Watkins LLP