EXHIBIT 5.1

                             PILLSBURY WINTHROP LLP
                                50 Fremont Street
                             San Francisco, CA 94105

                                  May 21, 2002




Advanced Fibre Communications, Inc.
1465 North McDowell Boulevard
Petaluma, CA  94954

Re: Registration Statement on Form S-8

Ladies and Gentlemen:

      We are acting as counsel for Advanced Fibre Communications, Inc., a
Delaware corporation (the "Company") in connection with the Registration
Statement on Form S-8 to be filed by the Company with the Securities and
Exchange Commission under the Securities Act of 1933 (the "Securities Act"),
relating to an aggregate of 3,694,597 shares of the Company's Common Stock, $.01
par value per share (the "Common Stock") issuable pursuant to the Advanced Fibre
Communications, Inc. 1996 Stock Incentive Plan and the AccessLan Communications,
Inc. 1997 Stock Plan (collectively, the "Plans"). We have reviewed and are
familiar with such corporate proceedings and other matters we have deemed
necessary for this opinion.

      Based on the foregoing, we are of the opinion that such shares of the
Common Stock of the Company, when duly issued and sold in accordance with the
Plans, and when payment therefor has been received by the Company as provided
for in the Plans, will be legally issued, fully paid and nonassessable.

      This opinion is limited to matters governed by the General Corporation Law
of the State of Delaware.

      We hereby consent to the filing of this opinion with the Securities and
Exchange Commission as Exhibit 5.1 to such Registration Statement. In giving
this consent, we do not thereby admit that we are within the category of persons
whose consent is required under Section 7 of the Securities Act or the rules and
regulations of the Securities and Exchange Commission promulgated thereunder.

                                                      Very truly yours,


                                                      /s/ Pillsbury Winthrop LLP