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                                                                     EXHIBIT 5.1

                                  July 21, 2000


Waste Connections, Inc.
620 Coolidge Drive, Suite 350
Folsom, CA  95630

          Re:    Waste Connections, Inc. Registration Statement on
                 Form S-8 for the Second Amended and Restated 1997 Stock Option
                 Plan

Ladies and Gentlemen:

               Reference is made to the Registration Statement on Form S-8 filed
by Waste Connections, Inc., a Delaware corporation (the "Company"), with the
Securities and Exchange Commission in connection with the proposed issuance and
sale by the Company of an additional 1,497,868 shares of Company's Common Stock,
par value $0.01 per share (the "Common Stock"). As counsel for the Company in
connection with the registration, we render the opinion set forth below.

               We have examined, and are familiar with, originals or copies,
certified or otherwise authenticated to our satisfaction, of documents,
corporate records and other writings which we consider relevant for the purpose
of this opinion. We have also reviewed the Amended and Restated Certificate of
Incorporation, the Amended and Restated Bylaws and pertinent resolutions of the
Board of Directors of the Company. In addition, we have ascertained or verified
other facts which we deem relevant for the purpose of this opinion.

               In connection with this examination, we have assumed the
genuineness of all signatures on original documents, the authenticity of all
documents submitted to us as originals, the conformity to originals of all
documents submitted to us as copies thereof, and the due execution and delivery
of all documents where due execution and delivery are a prerequisite to the
effectiveness thereof.

               Based upon the foregoing, and such other legal considerations as
we deem appropriate, we are of the opinion that:

               The additional 1,497,868 shares of Common Stock proposed to be
sold by the Company under the terms of the Company's Second Amended and Restated
1997 Stock Option Plan (the "Plan"), when sold and issued in accordance with the
terms of the Plan, will be validly issued, fully paid and non-assessable.

               We hereby consent to the filing of this opinion as an exhibit to
the Registration Statement.

                                           Very truly yours,


                                           /s/ Shartsis, Friese & Ginsburg LLP
                                           -----------------------------------

                                           SHARTSIS, FRIESE & GINSBURG LLP





                               Page-1 Exhibit 5.1