1
                                                                     EXHIBIT 5.1

                      [LETTERHEAD OF BAKER & BOTTS, L.L.P.]


014377.0164                                                     October 28, 1999


Baker Hughes Incorporated
3900 Essex Lane, Suite 1200
Houston, Texas 77027

Gentlemen:

         As set forth in the Registration Statement on Form S-3 (Registration
No. 333-87829) (the "Registration Statement") filed by Baker Hughes
Incorporated, a Delaware corporation (the "Company"), under the Securities Act
of 1933, as amended (the "Act"), relating to (i) unsecured debt securities of
the Company ("Debt Securities"), (ii) shares of preferred stock, par value $1.00
per share, of the Company ("Preferred Stock"), (iii) shares of common stock, par
value $1.00 per share, of the Company ("Common Stock") and (iv) warrants to
purchase other securities ("Warrants" and, together with the Debt Securities,
the Preferred Stock and the Common Stock, the "Securities") that may be issued
and sold by the Company from time to time pursuant to Rule 415 under the Act for
an aggregate initial offering price not to exceed $1,000,000,000, certain legal
matters in connection with the Securities are being passed upon for you by us.

         In our capacity as your counsel in the connection referred to above, we
have examined (i) the Restated Certificate of Incorporation and By-Laws of the
Company, each as amended to date (together, the "Charter Documents"), (ii) the
Indenture dated as of May 15, 1991 (the "Senior Debt Indenture") between the
Company and Citibank, N.A., as successor trustee to Morgan Guaranty Trust
Company of New York, pursuant to which senior Debt Securities may be issued,
(iii) the form of Indenture filed as Exhibit 4.5 to the Registration Statement
to be executed by the Company and the trustee thereunder (the "Subordinated Debt
Indenture") pursuant to which subordinated Debt Securities may be issued, and
(iv) the originals, or copies certified or otherwise identified, of corporate
records of the Company, certificates of public officials and of representatives
of the Company, statutes and other instruments and documents as a basis for the
opinions hereafter expressed.

         In connection with this opinion, we have assumed that (i) the
Registration Statement, and any amendments thereto (including post-effective
amendments), will have become effective under the Act; (ii) a prospectus
supplement will have been prepared and filed with the Securities and Exchange
Commission describing the Securities offered thereby; (iii) all Securities will
be issued and sold in compliance with applicable federal and state securities
laws and in the manner stated in the Registration Statement and the applicable
prospectus supplement; (iv) a definitive purchase, underwriting or similar
agreement with respect to any Securities offered will have been duly


   2

Securities and Exchange Commission     -2-                     October 28, 1999

authorized and validly executed and delivered by the Company and the other
parties thereto; (v) any securities issuable upon conversion, exchange,
redemption or exercise of any Securities being offered will be duly authorized,
created and, if appropriate, reserved for issuance upon such conversion,
exchange, redemption or exercise and (vi) with respect to shares of Common Stock
or Preferred Stock offered, there will be sufficient shares of Common Stock or
Preferred Stock authorized under the Company's Charter Documents and not
otherwise reserved for issuance.

          Based upon and subject to the foregoing, we are of the opinion that:

          1. The Company is a corporation duly organized and validly existing in
     good standing under the laws of the State of Delaware.

          2. With respect to shares of Common Stock, when (i) the Board of
     Directors of the Company or, to the extent permitted by the General
     Corporation Law of the State of Delaware and the Company's Charter
     Documents, a duly constituted and acting committee thereof (such Board of
     Directors or committee being hereinafter referred to as the "Board") has
     taken all necessary corporate action to approve the issuance thereof and
     the terms of the offering of shares of Common Stock and related matters,
     and (ii) certificates representing the shares of Common Stock have been
     duly executed, countersigned, registered and delivered, or if
     uncertificated, valid book-entry notations are made in the share register
     of the Company, either (a) in accordance with the applicable definitive
     purchase, underwriting or similar agreement approved by the Board upon
     payment of the consideration therefor (not less than the par value of the
     Common Stock) provided for therein, or (b) upon conversion, exchange,
     redemption or exercise of any other Security, in accordance with the terms
     of such Security or the instrument governing such Security providing for
     such conversion, exchange, redemption or exercise as approved by the Board,
     for the consideration approved by the Board (not less than the par value of
     the Common Stock), the shares of Common Stock will be duly authorized,
     validly issued, fully paid and non-assessable.

          3. With respect to shares of Preferred Stock, when (i) the Board has
     taken all necessary corporate action to approve and establish the terms of
     the shares of Preferred Stock, to approve the issuance thereof and the
     terms of the offering thereof and related matters, including the adoption
     of a Certificate of Designations relating to such Preferred Stock (a
     "Certificate of Designations"), and such Certificate of Designations has
     been filed with the Secretary of State of the State of Delaware, and (ii)
     certificates representing the shares of Preferred Stock have been duly
     executed, countersigned, registered and delivered, or if uncertificated,
     valid book-entry notations are made in the share register of the Company,
     either (a) in accordance with the applicable definitive purchase,
     underwriting or similar agreement approved by the Board upon payment of the
     consideration therefor (not less than the par value of the Preferred Stock)
     provided for therein, or (b) upon conversion, exchange, redemption or
     exercise of any other Security, in accordance with the terms of such
     Security


   3

Securities and Exchange Commission     -3-                     October 28, 1999


     or the instrument governing such Security providing for such conversion,
     exchange, redemption or exercise as approved by the Board, for the
     consideration approved by the Board (not less than the par value of the
     Preferred Stock), the shares of Preferred Stock will be duly authorized,
     validly issued, fully paid and non-assessable.

          4. With respect to Debt Securities to be issued under the Senior Debt
     Indenture, when (i) the Board has taken all necessary corporate action to
     approve and establish the terms of such Debt Securities, to approve the
     issuance thereof and the terms of the offering thereof and related matters,
     and (ii) such Debt Securities have been duly executed, authenticated,
     issued and delivered in accordance with both the provisions of the Senior
     Debt Indenture and either (a) the provisions of the applicable definitive
     purchase, underwriting or similar agreement approved by the Board upon
     payment of the consideration therefor provided for therein or (b) upon
     conversion, exchange, redemption or exercise of any other Security, in
     accordance with the terms of such Security or the instrument governing such
     Security providing for such conversion, exchange, redemption or exercise as
     approved by the Board, for the consideration approved by the Board, such
     Debt Securities will constitute legal, valid and binding obligations of the
     Company, enforceable against the Company, except as the enforceability
     thereof is subject to the effect of (i) bankruptcy, insolvency,
     reorganization, moratorium, fraudulent conveyance or other laws relating to
     or affecting creditors' rights generally and (ii) general principles of
     equity (regardless of whether such enforceability is considered in a
     proceeding in equity or at law).

          5. With respect to Debt Securities to be issued under the Subordinated
     Debt Indenture, when (i) the Subordinated Debt Indenture has been duly
     authorized and validly executed and delivered by the Company to the trustee
     thereunder, (ii) the Subordinated Debt Indenture has been duly qualified
     under the Trust Indenture Act of 1939, as amended, (iii) the Board has
     taken all necessary corporate action to approve and establish the terms of
     such Debt Securities, to approve the issuance thereof and the terms of the
     offering thereof and related matters, and (iv) such Debt Securities have
     been duly executed, authenticated, issued and delivered in accordance with
     both the provisions of the Subordinated Debt Indenture and either (a) the
     provisions of the applicable definitive purchase, underwriting or similar
     agreement approved by the Board upon payment of the consideration therefor
     provided for therein or (b) upon conversion, exchange, redemption or
     exercise of any other Security, in accordance with the terms of such
     Security or the instrument governing such Security providing for such
     conversion, exchange, redemption or exercise as approved by the Board, for
     the consideration approved by the Board; such Debt Securities will
     constitute legal, valid and binding obligations of the Company, enforceable
     against the Company, except as the enforceability thereof is subject to the
     effect of (i) bankruptcy, insolvency, reorganization, moratorium,
     fraudulent conveyance or other laws relating to or affecting creditors'
     rights generally and (ii) general principles of equity (regardless of
     whether such enforceability is considered in a proceeding in equity or at
     law).


   4

Securities and Exchange Commission     -4-                     October 28, 1999


          6. With respect to Warrants, when (i) the Board has taken all
     necessary corporate action to approve the creation of and the issuance and
     terms of the Warrants, the terms of the offering thereof and related
     matters, (ii) the Warrant Agreement or Agreements relating to the Warrants
     have been duly authorized and validly executed and delivered by the Company
     and the Warrant Agent appointed by the Company, and (iii) the Warrants or
     certificates representing the Warrants have been duly executed,
     countersigned, registered and delivered in accordance with the appropriate
     Warrant Agreement or Agreements and the applicable definitive purchase,
     underwriting or similar agreement approved by the Board upon payment of the
     consideration therefor provided for therein, the Warrants will be duly
     authorized and validly issued.

         We hereby consent to the filing of this opinion of counsel as Exhibit
5.1 to the Registration Statement. We also consent to the reference to our Firm
under the heading "Legal Opinions" in the prospectus forming a part of the
Registration Statement. In giving this consent, we do not hereby admit that we
are in the category of persons whose consent is required under Section 7 of the
Act.

                                         Very truly yours,

                                         BAKER & BOTTS, L.L.P.


JDK/TRF