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                                                                     EXHIBIT 5.1



                 LETTERHEAD OF SHARTSIS, FRIESE & GINSBURG LLP








                                  July 12, 2001








Waste Connections, Inc.
620 Coolidge Drive, Suite 350
Folsom, CA  95630-3155

Ladies and Gentlemen:

        We have acted as counsel for Waste Connections, Inc., a Delaware
corporation (the "Company"), in connection with its Registration Statement on
Form S-3 (Reg. No. 33-62322) and Pre-Effective Amendment No. 1 thereto, which
the Company has filed with the Securities and Exchange Commission pursuant to
the Securities Act of 1933, as amended (the "Act"), relating to (i) $150,000,000
aggregate principal amount of 5.5% Convertible Subordinated Notes due 2006 (the
"Notes") that the Company issued in a private placement in April and May 2001
pursuant to section 4(2) of the Act and Rule 144A under the Act, and (ii) up to
a total of 3,944,775 shares (the "Shares") of the Company's Common Stock, par
value $0.01 per share, issuable upon conversion of the Notes. Such Registration
Statement, including all exhibits thereto and all documents incorporated therein
by reference, is referred to below as the "Registration Statement."

The Notes were issued pursuant to a certain Purchase Agreement dated March 30,
2001, between the Company and Merrill Lynch, Pierce, Fenner & Smith
Incorporated, as the initial purchaser of the Notes (the "Note Purchase
Agreement"), and a related Indenture (the "Indenture") dated as of April 4,
2001, between the Company and State Street Bank and Trust Company of California,
National Association, as trustee (the "Trustee"). The Notes and the Shares (if
and when issued) may be resold from time to time for the account of certain
persons who are referred to in the Registration Statement as the "Selling
Holders." The Company is

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July 12, 2001
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obligated to issue Shares to the Selling Holders upon conversion of the Notes in
accordance with the terms of the Notes, the Note Purchase Agreement and the
Indenture.

        We rendered legal services to the Company in the course of the Company's
preparation of the Registration Statement. In connection therewith, we have made
such examination of matters of law and of fact as we considered appropriate or
advisable for purposes hereof. As to matters of fact material to the opinions
expressed herein, we have relied upon the representations and warranties as to
factual matters contained in and made by the Company pursuant to the Note
Purchase Agreement and upon certificates and statements of government officials
and of officers of the Company. We have been furnished and have examined
originals, or copies certified or otherwise identified to our satisfaction as
being true copies of the originals, of such records of the Company, agreements
and other instruments, certificates of officers, agents and representatives of
the Company, certificates of public officials and other documents as we have
deemed necessary.

        In making such examination, we have assumed the genuineness of all
signatures, the authenticity of all records, documents and certificates
submitted to us as originals, and the conformity with authentic originals of all
such items submitted to us as copies. For purposes of rendering our opinions
herein, we have (a) assumed that the Note Purchase Agreement and the Indenture
(collectively, together with the Notes, the "Transaction Documents") have been
duly authorized, executed and delivered by each party thereto other than the
Company, that each such party other than the Company has the power to enter into
and perform all its obligations thereunder and has taken any and all necessary
action to authorize the Transaction Documents, that the Notes have been
authenticated by the Trustee and paid for and delivered in accordance with the
Note Purchase Agreement, and that the Transaction Documents constitute the
respective legal, valid, binding agreements of the parties thereto other than
the Company, enforceable against the parties thereto other than the Company in
accordance with their respective terms and (b) relied as to factual matters on,
and assumed the accuracy of, the representations and warranties of the Company
in the Note Purchase Agreement.

        The opinions below are subject to (a) the effect of bankruptcy,
insolvency, reorganization, arrangement, moratorium or other similar laws
relating to or affecting the rights of creditors, including, without limitation,
laws relating to fraudulent transfers or conveyances, preferences and equitable
subordination, and (b) limitations imposed by law or general principles of
equity on the availability of equitable remedies or the enforcement of
provisions of the Note Purchase Agreement or any documents executed pursuant to
or in connection with the Note Purchase Agreement.

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

        1.     The Notes, when issued, were duly authorized and legally issued
and are fully paid and non-assessable.

        2.     The Notes constitute valid and legally binding obligations of the
Company.



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July 12, 2001
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        3. The Shares are duly authorized, and, when issued upon conversion of
the Notes in accordance with the terms of the Notes, the Note Purchase Agreement
and the Indenture, 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 use
of our name under the caption "Legal Matters" in the Prospectus.


                                            Very truly yours,

                                            SHARTSIS, FRIESE & GINSBURG LLP

                                            By:    /s/ Carolyn S. Reiser