
<PAGE>   1
                                                                     EXHIBIT 5.1






                





                                 May 31, 1995




USA Waste Services, Inc.
5000 Quorum, Suite 300
Dallas, Texas  75240


Gentlemen:

         We have acted as counsel for USA Waste Services, Inc., an Oklahoma
corporation (the "Company"), in connection with the filing of the Registration
Statement on Form S-8 for the Company's Employee Savings Plan (the "Plan") with
respect to the registration of 500,000 shares of the Common Stock, $.01 par
value (the "Common Stock"), of the Company, for issuance and sale from time to
time by the Company to the Plan.

         We have made such inquiries and examined such documents as we have
considered necessary or appropriate for purposes of giving the opinions
hereinafter set forth, including the examination of executed or conformed
counterparts, or copies certified or otherwise proved to our satisfaction, of
the following:

         (a)     the Certificate of Incorporation of the Company as filed with
the Secretary of State of Oklahoma on September 30, 1987, as amended;

         (b)     the By-laws of the Company;

         (c)     the Plan; and 

         (d)     the Registration Statement on Form S-8 of the Company filed
with the Securities and Exchange Commission with respect to the Plan (the 
"Registration Statement").

         We have assumed the genuineness and authenticity of all signatures on
all original documents, the authenticity of all documents submitted to us as
originals, the conformity to originals of all documents submitted to us as
copies and the due authorization, execution, delivery or recordation of all
documents where due authorization, execution or recordation or prerequisites to
the effectiveness thereof.

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USA Waste Services, Inc.
Page 2
May   , 1995

         Based upon the foregoing, and having regard for such legal
considerations as we deem relevant, we are of the opinion that:

         (i)     the Company is a corporation duly organized, validly existing
and in good standing under the laws of the States of Oklahoma;

         (ii)    the authorized capital of the Company consists of 50,000,000
shares of Common Stock, of which, as of March 31, 1994, 22,678,874 were issued 
and outstanding, and 10,000,000 shares of Preferred Stock, $.01 par value, of 
which, as of the date hereof, no shares are issued and outstanding; and

         (iii)   the 500,000 shares of Common Stock registered under the
Registration Statement are duly authorized and when issued by the Company will 
be legally issued, fully paid and non-assessable.

         We hereby consent to the filing of this opinion with the Securities and
Exchange Commission as an exhibit to the Registration Statement and to the
Statements made regarding our Firm and to the use of our name under the heading
"Legal Matters" in the prospectus constituting a part of the Registration
Statement.

                                                   Very truly yours,




                                                   SNELL & SMITH, A Professional
                                                        Corporation










