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                                                                     EXHIBIT 5.1

                             SACHNOFF & WEAVER, LTD.
                        30 SOUTH WACKER DRIVE, 29TH FLOOR
                             CHICAGO, ILLINOIS 60606


                                 April 13, 1999

USFreightways Corporation
9700 Higgins Road, Suite 570
Rosemont, Illinois 60018

Dear Ladies and Gentlemen:

         We have acted as counsel to USFreightways Corporation, a Delaware
corporation (the "Company"), in connection with the Registration Statement on
Form S-3 (the "Registration Statement"), filed by the Company under the
Securities Act of 1933, as amended (the "Act"), with the Securities and Exchange
Commission (the "Commission"), relating to the proposed sale of $100,000,000
principal amount of notes (the "Notes") of the Company. We have examined the
Registration Statement, and we have reviewed such other documents and have made
such further investigations as we have deemed necessary to enable us to express
the opinion hereinafter set forth.

         We hereby advise you that in our opinion, when the Registration
Statement becomes effective under the Act, the indenture relating to the Notes
(the "Indenture") has been duly authorized, executed and delivered and the Notes
have been duly executed and authenticated in accordance with the Indenture and
issued and sold as contemplated in the Registration Statement, the Notes will
constitute valid and legally binding obligations of the Company, subject to
bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium or
other similar laws relating to or affecting creditors' rights and to general
equity principles.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to us under the caption "Legal
Opinions" in 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 Securities Act of 1933 or the rules and regulations of
the Securities and Exchange Commission.


                                                   Very truly yours,

                                                   /s/ Sachnoff & Weaver, Ltd.

                                                 
                                                   SACHNOFF & WEAVER, LTD.