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                                                                   Exhibit 10.37

                                                                  EXECUTION COPY


                      AMENDMENT NO. 1, WAIVER AND CONSENT

     AMENDMENT NO. 1, WAIVER AND CONSENT to the Credit Agreements (hereinafter
defined), dated as of May 26, 1999, among Advanced Radio Telecom Corp. ("ART"),
the Lenders named in the Credit Agreements and Lucent Technologies Inc., as
Administrative Agent.  Capitalized terms used herein without definition shall
have the meaning specified in the Credit Agreements.

     WHEREAS, ART and the Lenders are parties to that certain Credit Agreement
(the "PM Credit Agreement"), dated as of September 17, 1998;

     WHEREAS, ART and the Lenders are parties to that certain Working Capital
Credit Agreement (the "WC Credit Agreement", together with the PM Credit
Agreement, the "Credit Agreements") dated as of September 17, 1998;

     WHEREAS, ART is entering into a transaction (the "Oak Transaction")
pursuant to which Oak Investment Partners and certain other investors
("Investors") will purchase Series A and Series B Preferred Stock of ART in
accordance with the terms set forth in a Preferred Stock Purchase Agreement
dated as of May __, 1999 among ART and the Investors (the "SPA") in exchange for
an investment of approximately $251,000,000 (the "Oak Investment"), subject to
the approval of ART's shareholders;

     WHEREAS, pending such shareholder approval, the Investors will advance all
or part of the Oak Investment as a bridge loan to ART (the "Bridge Loan"), with
the principal amount plus accrued interest of the Bridge Loan to be applied to
the purchase price of the Series A and Series B Preferred Stock at closing;

     WHEREAS, ART has requested that the Lender amend the Credit Agreements as
set forth in Section 1 below and waive compliance with certain provisions in the
Credit Agreements, and the Lenders are willing to amend the Credit Agreements
and so waive in accordance with the terms and conditions hereof;

     NOW THEREFORE, in consideration of the foregoing and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto hereby agree as follows:
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     1. Amendments to Credit Agreements.
        -------------------------------

          1.1  Amendments to PM Credit Agreement
               ---------------------------------

               1.1.1 Definitions.  Section 1.01 of the PM Credit Agreement is
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hereby amended to add the following definition in alphabetical order in such
section:

                     "Oak Transaction" means an investment of approximately
                     $250,000,000 by Oak Investment Partners and certain other
                     investors in Series A and Series B Preferred Stock of the
                     Borrower and related transactions pursuant to a Preferred
                     Stock Purchase Agreement dated May __, 1999 among the
                     Borrower and such investors (the "SPA"), including a bridge
                     loan to the Borrower pending the approval of the Oak
                     Transaction by stockholders of the Borrower, on terms
                     substantially similar to the terms set forth in the term
                     sheet attached as Appendix I to Amendment No. 1, Waiver and
                     Consent to this Agreement dated as of May __, 1999.

               1.1.2 Section 6.01 Indebtedness.  Section 6.01 of the PM Credit
                     -------------------------
Agreement is hereby amended to add a new subsection (h) on page 70 as follows
and to renumber existing subsections (h) and (i) as subsections (i) and (j),
respectively:

                    "(h) Indebtedness in an aggregate principal amount not
                    exceeding $50,000,000, consisting of a bridge loan or bridge
                    loans to the Borrower in connection with the Oak Transaction
                    on the terms set forth in Section 1.3 of the SPA and in the
                    notes referenced therein;"

          1.2  Amendments to Working Capital Credit Agreement.
               ----------------------------------------------

               1.2.1 Definitions.  Section 1.01 of the WC Credit Agreement is
                     -----------
hereby amended to add the following definition in alphabetical order in such
section:

                    "Oak Transaction" means an investment of approximately
                    $250,000,000 by Oak Investment Partners and certain other
                    investors in Series A and Series B Preferred Stock of the
                    Borrower and related transactions pursuant to a Preferred
                    Stock Purchase Agreement dated May __, 1999 among the
                    Borrower and such investors (the "SPA"), including a bridge
                    loan to the Borrower pending the approval of the Oak
                    Transaction by stockholders of the Borrower, on terms
                    substantially similar to

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                    the terms set forth in the term sheet attached as Appendix I
                    to Amendment No. 1, Waiver and Consent to this Agreement
                    dated as of May __, 1999.

               1.2.2 Definition of Maturity Date.  Section 1.01 of the WC
                     ---------------------------
Credit Agreement is hereby amended by deleting the words "June 30, 1999"
appearing in the definition of "Maturity Date" and replacing them with the
phrase "the earlier to occur of the 150th day after the date the SPA is signed
and the date of the final vote of ART's stockholders on the Oak Transaction."

               1.2.3 Definition of Prepayment Event.  The definition of
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"Prepayment Event" in Section 1.01 of the WC Credit Agreement is hereby amended
to add the following words at the end of such definition:

                     "provided further, that none of the funds received in
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                     connection with the Oak Transaction shall be deemed to be
                     Net Proceeds of a Prepayment Event or Net Proceeds received
                     in respect of events described in clauses (a) and (b) above
                     for purposes of calculating the first $50,000,000 of Net
                     Proceeds pursuant to the first proviso of this definition."

               1.2.4 Section 2.16 Extension of Maturity Date.  Section 2.16
                     ---------------------------------------
of the WC Credit Agreement is hereby amended by deleting the last proviso to the
last sentence thereof.

               1.2.5 Section 6.01 Indebtedness.  Section 6.01 of the WC
                     -------------------------
Credit Agreement is hereby amended by (a) deleting the word "and" appearing at
the end of clause (f) thereof, (b) deleting the period at the end of clause (g)
thereof and substituting therefor "; and" and (c) adding a new subsection (h) on
page 50 as follows:

                    "(h) Indebtedness in an aggregate principal amount not
                    exceeding $50,000,000, consisting of a bridge loan or bridge
                    loans to the Borrower in connection with the Oak Transaction
                    on the terms set forth in Section 1.3 of the SPA and in the
                    notes referenced therein,"

     2.  Waiver of Certain Provisions of the Credit Agreements.
         -----------------------------------------------------

          2.1  PM Credit Agreement.  The Lender hereby waives (i) any
               -------------------
requirement for prepayment of Borrowings under Section 2.09(e) of the PM Credit
Agreement as a result of any Repayment of the Bridge Loan, (ii) any Event of
Default under Article VII (m) of the PM Credit Agreement related to the Oak
Transaction; provided that the Investors do not purchase

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securities representing more than 45% of the voting power of ART's outstanding
capital stock and (iii) the provisions of Sections 6.21 through and including
6.23 of the PM Credit Agreement, which waiver shall extend for a period
beginning on the date hereof and terminating on October 31, 1999.

          2.2  WC Credit Agreement.  The Lender hereby waives (i) any Event of
               -------------------
Default under Article VII(l) of the WC Credit Agreement related to the Oak
Transaction and (ii) the provisions of Sections 6.15 through and including 6.16
of the WC Credit Agreement, which waiver shall extend for a period beginning on
the date hereof and terminating on October 31, 1999.

     3.   Ratification.  Except as provided herein, the Credit Agreements and
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the Loan Documents are each in all respects ratified and confirmed and the terms
and conditions thereof in all respects remain in full force and effect.

     4.   Governing Law.  This Agreement shall in all respects be governed by,
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and construed and enforced in accordance with the laws of the State of New York.

     5.   Miscellaneous.  This Agreement shall be binding upon and inure to the
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benefit of and be enforceable by the respective successors and assigns of the
parties hereto.  This Agreement embodies the entire agreement and understanding
between ART and the Lender and supersedes all prior agreements and
understandings relating to the subject matter hereof, except as otherwise
provided in Section 3 hereof.  If any provision hereof or any application
thereof shall be invalid or unenforceable, the remainder hereof and any other
application of such provision shall not be affected thereby.

IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed
by their respective representatives thereunto duly authorized as of the date
first above written.

                              ADVANCED RADIO TELECOM CORP.


                              By:  /s/ R. S. McCambridge
                                   ---------------------------------------------
                              Name:  R. S. McCambridge
                              Title: Executive Vice President & CFO

                              LUCENT TECHNOLOGIES INC.
                              individually and as Administrative Agent


                              By:  /s/ Paul A. Hayes
                                   ---------------------------------------------
                              Name:  Paul A. Hayes
                              Title: Director, NA Customer Finance

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