<PAGE>

                                                                   EXHIBIT 10.35

                                                                  Execution Copy


                         REGISTRATION RIGHTS AGREEMENT

     This Registration Rights Agreement is dated as of June 1, 1999 (this
"Agreement"), among Advanced Radio Telecom Corp., a Delaware corporation (the
"Company"), and the purchasers listed on Schedule I hereto (the "Purchasers").

     WHEREAS, contemporaneously with the execution and delivery of this
Agreement, the Company and the Series A Purchasers have entered into a Preferred
Stock Purchase Agreement dated as of June 1, 1999 (as in effect from time to
time, the "Purchase Agreement") in connection with the issuance and sale by the
Company to the Purchasers of certain shares (the "Shares") of the Company's
Series A Convertible Preferred Stock, $0.001 par value per share, and Series B
Non-voting Convertible Preferred Stock, $0.001 par value per share
(collectively, the "Preferred Stock"); and

     WHEREAS, it is a condition to the purchase of the Shares under the Purchase
Agreement that the Company and the Purchasers enter into this Agreement;

     NOW THEREFORE, in consideration of the premises and mutual covenants and
obligations hereinafter set forth, the Company and the Purchasers hereby agree
as follows:

          SECTION 1.   DEFINITIONS.  As used in this Agreement, the following
                       -----------
terms shall have the following meanings:

          "COMMISSION" shall mean the Securities and Exchange Commission or any
other Governmental Authority at the time administering the Securities Act.

          "COMMON STOCK" shall mean the Company's common stock, $0.001 par value
per share.

          "EXCHANGE ACT" shall mean the Securities Exchange Act of 1934 or any
successor Federal statute, and the rules and regulations of the Commission
promulgated thereunder, all as the same shall be in effect from time to time.

          "GOVERNMENTAL AUTHORITY" shall mean a domestic or foreign, federal,
state or local governmental entity (including a department, agency, bureau, or
political subdivision of such governmental entity).

          "INSPECTORS" shall have the meaning given to it in Section 5(i).
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          "INVESTORS" means the Purchasers and any other Person who becomes a
party to this Agreement either as an Investor pursuant to Section 13 hereof or
through the operation of Section 7.12 of the Purchase Agreement allowing the
Purchasers to assign their rights under the Purchase Agreement to certain
affiliates.

          "LUCENT AGREEMENT" means the Registration Rights Agreement dated
August 26, 1998 between the Company and Lucent Technologies, Inc.

          "MAJORITY OF THE INVESTORS" means those Investors who hold in the
aggregate in excess of 50% of the Registrable Shares (based on common stock
equivalents) held by all of the Investors.

          "MATERIAL TRANSACTION" means any material transaction in which the
Company or any of its material subsidiaries proposes to engage or is engaged,
including a purchase or sale of assets or securities, financing, merger,
consolidation, tender offer or any other transactions that would require
disclosure pursuant to the Exchange Act, and with respect to which the Board of
Directors of the Company reasonably has determined in good faith that compliance
with this Agreement may reasonably be expected to either materially interfere
with the Company's or such subsidiary's ability to consummate such transaction
in a timely fashion or require the Company to disclose material, non-public
information prior to such time as it would otherwise be required to be disclosed
and that such disclosure would not be in the best interests of the Company to
disclose at that time.

          "NASD" shall have the meaning given to it in Section 6(m).

          "ORIGINAL AGREEMENT" means the Second Restated and Amended
Registration Rights Agreement dated July 3, 1996, among the Company and the
other parties identified therein, as amended on October 16, 1996.

          "OTHER SHARES" shall mean at any time those shares of Common Stock
which do not constitute Primary Shares or Registrable Shares.

          "PERSON" shall be construed as broadly as possible and shall include
an individual or natural person, a partnership (including a limited liability
partnership), a corporation, an association, a joint stock company, a limited
liability company, a trust, a joint venture, an unincorporated organization and
a Governmental Authority.

          "PRIMARY SHARES" shall mean at any time the authorized but unissued
shares of Common Stock or shares of Common Stock held by the Company in its
treasury.

          "PURCHASER" shall have the meaning given to it in the preamble.

          "RECORDS" shall have the meaning given to it in Section 5(i).

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          "REGISTRABLE SHARES" shall mean, at any time, and with respect to any
Investor, the Restricted Shares held by such Investor.  As to any particular
Registrable Shares, once issued, such Registrable Shares shall cease to be
Registrable Shares when (A) they have been registered under the Securities Act,
the Registration Statement in connection therewith has been declared effective
and they have been disposed of pursuant to and in the manner described in such
effective Registration Statement, (B) they are sold or distributed pursuant to
Rule 144, (C) they have been otherwise transferred and new certificates or other
evidences of ownership for them not bearing a restrictive legend and not subject
to any stop transfer order or other restriction on transfer shall have been
delivered by the Corporation or the issuer of other securities issued in
exchange for the Registrable Shares, or (D) they have ceased to be outstanding.

          A "REGISTRATION STATEMENT" means (A) a registration statement filed by
the Company in accordance with Section 5 of the Securities Act, including
exhibits and financial statements thereto, in the form in which it shall become
effective, the documents incorporated by reference therein pursuant to Item 12
of Form S-3 (or any similar provision or forms then in force) under the
Securities Act and information deemed to be a part of such registration
statement pursuant to paragraph (B) of Rule 430A under the Securities Act (or
any similar provision then in force) and (B) in the event of any amendment
thereto after the effective date of the registration statement, then from and
after the effectiveness of the amendment, the registration statement as so
amended.

          "RESTRICTED SHARES" shall mean, at any time and with respect to any
Investor, the shares of Common Stock issued either upon conversion of the Shares
(or upon the conversion of any securities into which the Shares are convertible)
or the exercise of the Warrants which are held by such Investor.

          "RULE 144" shall mean Rule 144 promulgated under the Securities Act or
any successor rule thereto or any complementary rule thereto (such as Rule
144A).

          "SECURITIES ACT" shall mean the Securities Act of 1933 or any
successor Federal statute, and the rules and regulations of the Commission
thereunder, all as the same shall be in effect from time to time.

          "SHARES" shall have the meaning given to it in the preamble.

          "WARRANTS" shall mean the warrants to purchase Common Stock issued to
the Purchasers pursuant to the Purchase Agreement and which are exercisable in
certain events as set forth therein.

          SECTION 2.   REGISTRATIONS ON DEMAND.
                       -----------------------

               (a) Registration on Request.  At any time more than six months
                   -----------------------
     after the date hereof, a Majority of Investors may, by written notice to
     the Company, request

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     that the Company effect the registration under the Securities Act of
     Registrable Shares with an aggregate market value of at least $25 million
     based on the public trading price on the date of the request of the shares
     to be registered. If the Investors initiating such registration intend to
     distribute the Registrable Shares in an underwritten offering, they shall
     so state in their request. Promptly after receipt of such notice, the
     Company will give written notice of such requested registration to all
     other holders of Registrable Shares. The Company will then use its best
     efforts expeditiously to effect the registration under Securities Act of
     the Registrable Shares which the Company has been requested to register by
     such Investors, and all other Registrable Shares which the Company has been
     requested to register by other holders of Registrable Securities by notice
     delivered to the Company within 10 business days after the giving of such
     notice by the Company.

               (b) Registration on Form S-3.  For so long as the Company shall
                   ------------------------
     be qualified for the use of Form S-3 promulgated under the Securities Act
     or any successor form thereto, any one or more of the Investors shall have
     the right to request in writing registrations on Form S-3 or such successor
     form of Registrable Shares, which request or requests shall (i) specify the
     number of Registrable Shares intended to be sold or disposed of, which
     shall have an aggregate market value of at least $20 million based on the
     public trading price of the shares to be registered on the date of the
     request, and (ii) state the intended method of disposition of such
     Registrable Shares.  Promptly after receipt of any such request, the
     Company shall give written notice of such proposed registration to the
     other Investors.  The Company will then use its best efforts expeditiously
     to effect the registration under Securities Act of the Registrable Shares
     requested to be included in such proposed registration by such holders who
     respond in writing to the Company's notice within 10 business days after
     delivery of such Notice (which response shall specify the number of
     Registrable Shares proposed to be included in such registration).

               (c) Anything contained in Section 2(a) to the contrary
     notwithstanding, the Company may delay the filing or effectiveness of any
     registration pursuant to Sections 2(a) and 2(b) for a period of up to 90
     days  if (1) the Company in good faith determines that such registration
     would materially impede, delay or interfere with any material financing,
     offer or sale of equity securities or debt securities of the Company, or
     acquisition, disposition or other material transaction by the Company or
     any of its material subsidiaries, or (2) the Company in good faith
     determines that the Company is in possession of material non-public
     information the disclosure of which during the period specified in such
     notice the Company reasonably believes would not be in the best interests
     of the Company; provided that the Company may not take any action pursuant
     to this Section 2(c) for more than one 90 day period in any twelve month
     period.

               (d) A requested registration under Section 2(a) may be rescinded
     prior to such registration being declared effective by the Commission by
     written notice to the Company from Investors holding a majority of the
     Registrable Shares proposed to be registered pursuant to such registration
     statement pursuant to Section 2(a).

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               (e) The Company shall not be required to effect more than six
     registrations pursuant to Section 2(a) during the term of this Agreement,
     and shall not be required to effect more than two registrations pursuant to
     this Section 2 in any twelve month period; provided that a registration
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     statement shall be deemed not to have been prepared and filed if (A) the
     registration statement (i) is withdrawn by such Investors as a result of
     delay pursuant to Section 2(c), or (ii) does not become effective for any
     other reason except the withdrawal therefrom of 20% or more of the
     Registrable Shares requested to be included in such registration statement
     or the determination by selling Investors owning 30% or more of such
     Registrable Shares not to proceed with the contemplated distribution of
     such Registrable Shares or (B) the Company fails to use its best efforts to
     cause the registration statement to remain effective under the Securities
     Act and the Prospectus to remain current during the entire period referred
     to in Section 5(b).

          SECTION 3.   PIGGYBACK REGISTRATION.  If the Company at any time
                       ----------------------
proposes for any reason to register Primary Shares or Other Shares under the
Securities Act (other than on Form S-4 or Form S-8 promulgated under the
Securities Act or any successor forms thereto and other than pursuant to a
registration statement covered by Rule 462 promulgated under the Securities
Act), it shall promptly give written notice to each Investor of its intention so
to register the Primary Shares or Other Shares and, upon the written request,
given within 10 business days after delivery of any such notice by the Company,
of any such Investor to include in such registration Registrable Shares (which
request shall specify the number of Registrable Shares proposed to be included
in such registration), the Company shall use its best efforts to cause all such
Registrable Shares to be included in such registration on the same terms and
conditions as the securities otherwise being sold in such registration;
provided, however, that if the managing underwriter advises the Company that the
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inclusion of all Registrable Shares or Other Shares proposed to be included in
such registration would interfere with the successful marketing (including
pricing) of Primary Shares proposed to be registered by the Company, then the
number of Primary Shares, Registrable Shares and Other Shares proposed to be
included in such registration shall be included in the following order:

               (a)  first, the Primary Shares;

               (b) second, the Other Shares or other securities, if any,
     entitled to be included in such registration pursuant to the Original
     Agreement;

               (c) third, the Other Shares or other securities, if any, entitled
     to be included in such registration pursuant to the Lucent Agreement;

               (d) fourth, the Registrable Shares requested to be included
     pursuant to this Agreement; and

               (e) fifth, any Other Shares or securities requested to be
     included.

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<PAGE>

The Company shall be under no obligation to complete any offering it proposes to
make and shall incur no liability to any Investor for its failure to do so.  No
registration of Registrable Shares effected under this Section 3 shall relieve
the Company of any of its obligations to effect registrations of Registrable
Securities pursuant to Section 2 hereof.

          SECTION 4.   HOLDBACK AGREEMENT.  If the Company at any time shall
                       ------------------
register shares of Common Stock under the Securities Act for sale to the public
in an underwritten offering, each of the Investors agrees not to, directly or
indirectly, sell, seek registration under the Securities Act of, or otherwise
dispose of any shares or Common Stock or securities convertible into or
exchangeable for Common Stock (other than Registrable Shares included in such
registration pursuant to Section 2 or 3) without the prior written consent of
the managing underwriter for a period from two business days prior to the date
of the final prospectus pursuant to which such public offering shall be made
through 90 days after the date of such final prospectus or such longer period as
the Company's board of directors determines in good faith to be appropriate.

          SECTION 5.   PREPARATION AND FILING.  If and whenever the Company is
                       ----------------------
under an obligation pursuant to the provisions of this Agreement to use its best
efforts to effect the registration of any Registrable Shares, the Company shall,
as expeditiously as practicable:

               (a) prepare and file with the Commission a registration statement
     with respect to such Registrable Securities and (in the case of a
     registration pursuant to Section 2 hereof) use its best efforts to cause
     such registration statement to become effective;

               (b) prepare and file with the Commission such amendments and
     supplements to such registration statement and the prospectus used in
     connection therewith as may be necessary to keep such registration
     statement effective for at least a period of 180 days or until all of such
     Registrable Shares have been disposed of (if earlier) and to comply with
     the provisions of the Securities Act with respect to the sale or other
     disposition of such Registrable Shares, provided that the Company may
     suspend (and such suspension shall extend such 180-day period by the same
     duration) for up to 45 days the effectiveness of such registration
     statement, or elect not to amend such registration statement or supplement
     the prospectus used in connection therewith so that sales may not be made
     thereon for up to 45 days (and such period of delay shall extend such 180-
     day period by the same duration), if the making of disclosures required by
     such registration statement would have a material adverse affect upon the
     Company or its securities and such disclosures are not otherwise required
     to be made; provided that any such suspensions, along with suspensions or
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     delays pursuant to Section 2(c) hereof are limited to an aggregate of 90
     days in any twelve month period;

                                      -6-
<PAGE>

               (c) notify in writing one firm acting as counsel for the Selling
     Investors on whose behalf the Registrable Shares are being registered
     promptly (i) of any comments by the Commission with respect to such
     registration statement or prospectus, or any request by the Commission for
     the amending or supplementing thereof or for additional information with
     respect thereto, (ii) of the issuance by the Commission of any stop order
     suspending the effectiveness of such registration statement or prospectus
     or any amendment or supplement thereto or the initiation of any proceedings
     for that purpose and (iii) of the receipt by the Company of any
     notification with respect to the suspension of the qualification of such
     Registrable Shares for sale in any jurisdiction or the initiation or
     threatening of any proceeding for such purposes;

               (d) use its best efforts to register or qualify such Registrable
     Shares under such other securities or blue sky laws of such jurisdictions
     as any seller of Registrable Shares reasonably requests and do any and all
     other acts and things which may be reasonably necessary or advisable to
     enable such seller of Registrable Shares to consummate the disposition in
     such jurisdictions of the Registrable Shares owned by such seller;
     provided, however, that the Company will not be required to qualify
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     generally to do business, subject itself to general taxation or consent to
     general service of process in any jurisdiction where it would not otherwise
     be required so to do but for this paragraph (d);

               (e) furnish to each seller of such Registrable Shares such number
     of conformed copies of such registration statement and of each such
     amendment and supplement thereto (in each case including all exhibits and
     documents incorporated by reference therein, except that the Company shall
     not be obligated to furnish any such seller with more than two copies of
     such exhibits and documents), such number of copies of the prospectus
     included in such registration statement (including any summary prospectus
     or other prospectus, including a preliminary prospectus), in conformity
     with the requirements of the Securities Act, and such other documents as
     such seller of Registrable Shares may reasonably request in order to
     facilitate the public sale or other disposition of such Registrable Shares;

               (f) use its best efforts to cause such Registrable Shares to be
     registered with or approved by such other governmental agencies or
     authorities as may be necessary by virtue of the business and operations of
     the Company to enable the seller or sellers thereof to consummate the
     disposition of such Registrable Shares;

               (g) notify on a timely basis each seller of such Registrable
     Shares at any time when a prospectus relating to such Registrable Shares is
     required to be delivered under the Securities Act within the appropriate
     period mentioned in subparagraph (a) of this Section 5, of the happening of
     any event as a result of which the prospectus included in such registration
     statement, as then in effect, includes an untrue statement of a material
     fact or omits to state a material fact required to be stated therein or
     necessary to make the

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<PAGE>

     statements therein not misleading in light of the circumstances then
     existing and, at the request of such seller, prepare and furnish to such
     seller a reasonable number of copies of a supplement to or an amendment of
     such prospectus as may be necessary so that, as thereafter delivered to the
     offerees of such shares, such prospectus shall not include an untrue
     statement of a material fact or omit to state a material fact required to
     be stated therein or necessary to make the statements therein not
     misleading in light of the circumstances then existing;

               (h) give each seller of such Registrable Shares, any underwriter
     participating in any disposition pursuant to such registration statement
     and any attorney, accountant or other agent retained by any such seller or
     underwriter (collectively, the "Inspectors") the opportunity to participate
     in the preparation of such registration statement, each prospectus included
     therein, and each amendment and supplement thereto, and give each Inspector
     all pertinent financial and other records, pertinent corporate documents
     and properties of the Company, as shall be reasonably necessary to enable
     them to exercise their due diligence responsibility;

               (i) use its best efforts to obtain, from its independent
     certified public accountants, a "cold comfort" letter in customary form and
     covering such matters of the type customarily covered by cold comfort
     letters;

               (j) use its best efforts to obtain, from its counsel, an opinion
     or opinions in customary form;

               (k) provide a transfer agent and registrar (which may be the same
     entity and which may be the Company) for such Registrable Shares;

               (l) issue to any underwriter to which any seller of Registrable
     Shares may sell shares in such offering, certificates evidencing such
     Registrable Shares;

               (m) use its best efforts to list such Registrable Shares on any
     national securities exchange on which any shares of the Common Stock are
     listed or for qualify such Registrable Shares for inclusion on the
     automated quotation system of the National Association of Securities
     Dealers, Inc. (the "NASD"), as applicable;

               (n) otherwise use its best efforts to comply with all applicable
     rules and regulations of the Commission, and make available to its security
     holders, as soon as reasonably practicable, earnings statements which need
     not be audited covering a period of 12 months beginning within three months
     after the effective date of the registration statement, which earnings
     statements shall satisfy the provisions of Section 11(a) of the Securities
     Act;

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<PAGE>

               (o) use its best efforts to take all other steps necessary to
     effect the registration of such Registrable Shares contemplated hereby;

               (p) if the registration involves an underwritten offering, enter
     into an underwriting agreement in customary form with the underwriter or
     underwriters selected for such underwriting and deliver to each selling
     Investor, its counsel and each underwriter of Registrable Shares owned by
     the Registering stockholders to be distributed pursuant to such
     registration, the certificates, opinions of counsel and comfort letters
     that are customarily delivered in connection with underwritten offerings.

               (q) before sales of Registrable Shares under a registration
     statement, cooperate with the selling Investors and each underwriter of
     Registrable Shares owned by the selling Investors to facilitate the timely
     preparation and delivery of certificates (not bearing any restrictive
     legends) representing the Registrable Shares to be sold under the
     Registration Statement and to enable such Registrable Shares to be in such
     denominations and registered in such names as the seller or the underwriter
     may request.

          Each holder of the Registrable Shares, upon receipt of any notice from
the Company of any event of the kind described in Section 5(g) hereof, shall
forthwith discontinue disposition of the Registrable Shares pursuant to the
registration statement covering such Registrable Shares until such holder's
receipt of the copies of the supplemented or amended Prospectus contemplated by
Section 5(g) hereof, and, if so directed by the Company, such holder shall
deliver to the Company all copies, other than permanent file copies then in such
holder's possession, of the most recent prospectus covering such Registrable
Shares at the time of receipt of such notice.

          SECTION 6.   EXPENSES.  All expenses incurred by the Company in
                       --------
complying with Section 5, including, without limitation, all registration and
filing fees (including all expenses incident to filing with the NASD), fees and
expenses of complying with securities and blue sky laws, printing expenses, and
fees and expenses of the Company's counsel and accountants shall be paid by the
Company; provided, however, that all underwriting discounts and selling
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commissions and all transfer taxes applicable to the Registrable Shares, and the
fees and expenses of counsel for the Investors on whose behalf the Registrable
Shares are being registered, shall not be borne by the Company but shall be
borne by the seller or sellers thereof, in proportion to the number of
Registrable Shares sold by such seller or sellers.

          SECTION 7.   INDEMNIFICATION.
                       ---------------

               (a) In connection with any registration of any Registrable Shares
     under the Securities Act pursuant to this Agreement, the Company shall
     indemnify and hold harmless the selling Investor, including its partners,
     directors and officers, each underwriter, broker or any other Person acting
     on behalf of such selling Investor and each other Person, if any, who
     controls any of the foregoing Persons within the meaning of the

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     Securities Act against any losses, claims, damages or liabilities, joint or
     several, to which any of the foregoing Persons may become subject under the
     Securities Act or otherwise, insofar as such losses, claims, damages or
     liabilities (or actions in respect thereof) arise out of or are based upon
     an untrue statement or alleged untrue statement of a material fact
     contained in the registration statement (including any documents
     incorporated by reference therein) under which such Registrable Shares were
     registered under the Securities Act, any preliminary prospectus or final
     prospectus contained therein, any amendment or supplement thereto or any
     document incident to registration or qualification of any Registrable
     Shares, or arise out of or are based upon the omission or alleged omission
     to state therein a material fact required to be stated therein or necessary
     to make the statements therein not misleading or, with respect to any
     prospectus, necessary to make the statements therein in light of the
     circumstances under which they were made not misleading, or any violation
     by the Company of the Securities Act or state securities or blue sky laws
     applicable to the Company and relating to action or inaction required of
     the Company in connection with such registration or qualification under
     such state securities or blue sky laws; and shall reimburse such selling
     Investor, such underwriter, such broker or such other Person acting on
     behalf of such selling Investor, including its partners, directors and
     officers and each such controlling Person for any legal or other expenses
     reasonably incurred by any of them in connection with investigating or
     defending any such loss, claim, damage, liability or action; provided,
     however, that the Company shall not be liable in any such case to the
     extent that any such loss, claim, damage or liability arises out of or is
     based upon an untrue statement or alleged untrue statement or omission or
     alleged omission made in said registration statement, preliminary
     prospectus, amendment, supplement or document incident to registration or
     qualification of any Registrable Shares in reliance upon and in conformity
     with written information furnished to the Company through an instrument
     duly executed by such selling Investor or underwriter, or a Person duly
     acting on their behalf, specifically for use in the preparation thereof.

               (b) In connection with any registration of Registrable Shares
     under the Securities Act pursuant to this Agreement, each selling Investor
     shall indemnify and hold harmless (in the same manner and to the same
     extent as set forth in the preceding paragraph of this Section 7) the
     Company, each director of the Company, each officer of the Company, each
     underwriter, broker or other Person acting on behalf of such seller, each
     Person who controls any of the foregoing Persons within the meaning of the
     Securities Act with respect to any statement or omission from such
     registration statement, any preliminary prospectus or final prospectus
     contained therein, any amendment or supplement thereto or any document
     incident to registration or qualification of any Registrable Shares, if
     such statement or omission was made in reliance upon and in conformity with
     written information furnished to the Company or such underwriter through an
     instrument duly executed by such seller or a Person duly acting on their
     behalf specifically for use in connection with the preparation of such
     registration statement, preliminary prospectus, final prospectus, amendment
     or supplement; provided, however,

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<PAGE>

     that the maximum amount of liability in respect of such indemnification
     shall be, limited, in the case of each selling Investor, to an amount equal
     to the net proceeds actually received by such selling Investor from the
     sale of Registrable Shares effected pursuant to such registration.

               (c) Promptly after receipt by an indemnified party of notice of
     the commencement of any action involving a claim referred to in the
     preceding paragraphs of this Section 7, such indemnified party will give
     written notice to the indemnifying party of the commencement of such
     action.  In case any such action is brought against an indemnified party,
     the indemnifying party will be entitled to participate in and to assume the
     defense thereof, jointly with any other indemnifying party similarly
     notified to the extent that it may wish, with counsel reasonably
     satisfactory to such indemnified party, and after notice from the
     indemnifying party to such indemnified party of its election so to assume
     the defense thereof, the indemnifying party shall not be responsible for
     any legal or other expenses subsequently incurred by the indemnified party
     in connection with the defense thereof; provided, however, that if any
     indemnified party shall have reasonably concluded that there may be one or
     more legal or equitable defenses available to such indemnified party which
     are additional to or conflict with those available to the indemnifying
     party, or that such claim or litigation involves or could have an effect
     upon matters beyond the scope of the indemnity agreement provided in this
     Section 7, the indemnifying party shall not have the right to assume the
     defense of such action on behalf of such indemnified party and such
     indemnifying party shall reimburse such indemnified party and, any Person
     controlling such indemnified party for that portion of the fees and
     expenses of any one counsel retained by the indemnified party which are
     reasonably related to the matters covered by the indemnity agreement
     provided in this Section 7.

               (d) If the indemnification provided for in this Section 7 is
     unavailable to an indemnified party with respect to any loss, claim, damage
     or liability referred to herein, then the indemnifying party, in lieu of
     indemnifying such indemnified party hereunder, shall contribute to the
     amounts paid or payable by such indemnified party as a result of such loss,
     claim, damage or liability in such proportion as is appropriate to reflect
     the relative fault of the indemnifying party on the one hand and of the
     indemnified party on the other in connection with the statements or
     omissions which resulted in such loss, claim, damage or liability as well
     as any other relevant equitable considerations, limited, in the case of
     each selling Investor, to an amount equal to the net proceeds actually
     received by such selling Investor from the sale of Registrable Shares
     effected pursuant to such registration.  The relative fault of the
     indemnifying party and of the indemnified party shall be determined by
     reference to, among other things, whether the untrue or alleged untrue
     statement of a material fact or the omission to state a material fact
     relates to information supplied by the indemnifying party or by the
     indemnified party and the parties' relative intent, knowledge, access to
     information and opportunity to correct or prevent such statement or
     omission.

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<PAGE>

          SECTION 8.   INFORMATION BY HOLDER.  Each holder of Registrable Shares
                       ---------------------
to be included in any registration shall furnish to the Company and the managing
underwriter such written information regarding such holder and the distribution
proposed by such holder as the Company or the managing underwriter may
reasonably request in writing and as shall be reasonably required in connection
with any registration, qualification or compliance referred to in this
Agreement.

          SECTION 9.   EXEMPT SALES.
                       ------------

               (a) The Company shall make all filings with the Commission
     required by Rule 144(c) (or any similar provision then in force) under the
     Securities Act to permit the sale of Registrable Shares by any holder
     thereof (other than an affiliate of the Company) to satisfy the conditions
     of Rule 144 (or any similar provision then in force).  The Company shall,
     promptly upon the written request of the holder of Registrable Shares,
     deliver to such holder a written statement as to whether the Company has
     complied with all such filing requirements.

               (b) Before sales of Registrable Shares proposed to be sold
     pursuant to an exemption from the registration requirements of the
     Securities Act, the Company shall cooperate with the holder of such
     Registrable Shares, to facilitate the timely preparation and delivery of
     certificates (not bearing any restrictive legends) representing such
     Registrable Shares, in connection with the closing of the sales and to
     enable such Registrable Shares to be in such denominations and registered
     in such names as the holder may request.

          SECTION 10.   NO CONFLICT OF RIGHTS.  The Company represents and
                        ---------------------
warrants to the Investors that the registration rights granted to the Investors
hereby do not conflict with any other registration rights granted by the
Company.  Notwithstanding anything to the contrary contained herein, the parties
hereto intend that the registration rights granted by this Agreement not
conflict with or impart the registration rights granted by the Original
Agreement and the Lucent Agreement, and this Agreement shall be interpreted
accordingly.  The Company shall not, after the date hereof, grant any
registration rights which conflict with, or have any priority over, the
registration rights granted hereby.  Without derogating from the generality of
this Section 10, after the date of this Agreement, the Company shall not enter
into, or amend or otherwise modify, any agreement to afford to any person other
than the Purchasers and the holders of Registrable Shares the right to require
the Company to include in any registration statement filed under Section 2 or
Section 3 hereof any securities of the Company pursuant to the exercise of any
"piggy-back" right under an agreement with the Company not in existence as of
the date of this Agreement unless such securities are junior in priority to the
Registrable Shares.  In any public offering pursuant to Section 2(a), the
managing underwriter shall be a nationally recognized investment banking firm
selected by the Company and reasonably acceptable to Two-Thirds in Interest of
the Investors.

                                      -12-
<PAGE>

          SECTION 11.   TERMINATION.  This Agreement shall terminate and be of
                        -----------
no further force or effect on the earlier of (i) the date when there shall not
be any Registrable Shares outstanding or (ii) the fifth anniversary of the date
hereof; provided, however, that a particular Investor's rights under Sections 2
        --------  -------
and 3 hereof shall cease to be in effect for so long as the Registrable Shares
held by such Investor may be sold by such Investor under Rule 144 and such
Registrable Shares constitute less than 1% of the class of the Company's
securities of which the Registrable Shares are a part.

          SECTION 12.   SUCCESSORS AND ASSIGNS.  This Agreement shall bind and
                        ----------------------
inure to the benefit of the Company and the Investors and, subject to Section
14, their respective successors and assigns.

          SECTION 13.   ASSIGNMENT.  Each Investor may assign its rights
                        ----------
hereunder to any purchaser from such Investor of  Restricted Shares with an
aggregate fair market value in excess of $3,000,000 at the time of such sale;
provided, however, that such purchaser shall, as a condition to the
--------  -------
effectiveness of such assignment, be required to execute a counterpart to this
Agreement agreeing to be treated as an Investor whereupon such purchaser shall
have the benefits of, and shall be subject to the restrictions contained in,
this Agreement.

          SECTION 14.   NOTICES.  All notices and other communications given or
                        -------
made pursuant hereto shall be in writing and shall be deemed to have been duly
given or made if and when delivered personally or by overnight courier to the
parties at the following addresses or sent by electronic transmission, with
confirmation received, to the telecopy numbers specified below (or at such other
address or telecopy number for a party as shall be specified by like notice):

                                      -13-
<PAGE>


                             (i) If to the Purchasers, to such address listed on
                      Schedule I hereto, with copies to:

                      Gunderson Dettmer Stough Villeneuve
                        Franklin & Hachigian, LLP
                      155 Constitution Drive
                      Menlo Park, CA  94025
                      Attn: Brooks Stough, Esq.
                      Telecopier No.: (650) 321-2800
                      Telephone No.: (650) 463-5370

                      O'Melveny & Myers, LLP
                      1999 Avenue of the Stars
                      Los Angeles, CA  90067-6035
                      Attn: Steven L. Grossman, Esq.
                      Telecopier No.: (310) 246-6779
                      Telephone No.: (310) 553-6700


                            (ii)  If to the Company:

                      Advanced Radio Telecom Corporation
                      500 108th Avenue NE, Suite 2600
                      Bellevue, WA  98004
                      Attn: Thomas M. Walker, Esq., General Counsel
                      Telecopier No.: (425) 990-1642 or (425) 688-0703
                      Telephone No.: (425) 990-1669

                      With a copy to:

                      Ropes & Gray
                      One International Place
                      Boston, MA  02110
                      Attn: Mary E. Weber, Esq.
                      Telecopier No.: (617) 951-7050
                      Telephone No.: (617) 951-7391


All such notices, requests, consents and other communications shall be deemed to
have been delivered (a) in the case of personal delivery, telex, telegram or
telecopy, on the date of such delivery, (b) in the, case of overnight courier,
on the next business day, and (c) in the case of mailing, on the third business
day following such mailing.

                                      -14-
<PAGE>

          SECTION 15.   MODIFICATIONS; AMENDMENTS; WAIVERS.  The terms and
                        ----------------------------------
provisions of this Agreement may not be modified or amended, nor may any
provision applicable to the Investors be waived, except pursuant to a writing
signed by (i) the Company and (ii) Two-Thirds in Interest of the Investors.

          SECTION 16.   COUNTERPARTS.  This Agreement may be executed in any
                        ------------
number of counterparts, and each such counterpart hereof shall be deemed to be
an original instrument, but all such counterparts together shall constitute but
one agreement.

          SECTION 17.   HEADINGS.  The headings of the various sections of this
                        --------
Agreement have been inserted for convenience of reference only and shall not be
deemed to be a part of this Agreement.

          SECTION 18.   SEVERABILITY.  It is the desire and intent of the
                        ------------
parties that the provisions of this Agreement be enforced to the fullest extent
permissible under the law and public policies applied in each jurisdiction in
which enforcement is sought.  Accordingly, if any provision of this Agreement
would be held in any jurisdiction to be invalid, prohibited or unenforceable for
any reason, such provision, as to such jurisdiction, shall be ineffective,
without invalidating the remaining provisions of this Agreement or affecting the
validity or enforceability of such provision in any other jurisdiction.
Notwithstanding the foregoing, if such provision could be more narrowly drawn so
as not to be invalid, prohibited or unenforceable in such jurisdiction, it
shall, as to such jurisdiction, be so narrowly drawn, without invalidating the
remaining provisions of this Agreement or affecting the validity or
enforceability of such provision in any other jurisdiction.

          SECTION 19.   GOVERNING LAW.  All questions concerning the
                        -------------
construction, interpretation and validity of this Agreement shall be governed by
and construed and enforced in accordance with the domestic laws of the State of
New York, without giving effect to any choice or conflict of law provision or
rule (whether in the State of New York or any other jurisdiction) that would
cause the application of the laws of any jurisdiction other than the State of
New York. In furtherance of the foregoing, the internal law of the State of New
York will control the interpretation and construction of this Agreement, even if
under such jurisdiction's choice of law or conflict of law analysis, the
substantive law of some other jurisdiction would ordinarily apply.

          SECTION 20.   LEGEND ON CERTIFICATES.  Any certificate representing
                        ----------------------
securities subject to this Agreement shall bear a legend in substantially the
following form:

               "The securities represented by this certificate are subject to a
               Registration Rights Agreement dated as of June __, 1999, as
               amended from time to time.  A copy thereof is available for
               inspection from the Company."

                                      -15-
<PAGE>

          SECTION 21.   COUNTERPARTS; VALIDITY.  This Agreement may be executed
                        ----------------------
in counterparts and telecopied signatures are effective.  The failure of any
Person holding Registrable Shares to execute this Agreement does not make it
invalid as against any other Person holding Registrable Shares.

          SECTION 22.   ENTIRE AGREEMENT.  This Agreement and the other
                        ----------------
documents, certificates, instruments, writings and agreements referred to herein
or delivered pursuant hereto contain the entire understanding of the parties
with respect to the subject matter hereof and supersede in their entirety any
and all prior agreements and understandings between any of the parties hereto
all of which are hereby terminated in their entirety and of no further force or
effect.

          SECTION 23.   AFFILIATE.  Nothing contained in this Agreement shall
                        ---------
constitute any Investor or any selling Investor an "affiliate" of the Company
within the meaning of the Securities Act or the Exchange Act, including, without
limitation, Rule 501 under the Securities Act and Rule 13e-3 under the Exchange
Act.

          SECTION 24.   FCC APPROVALS.  If the sale of Registrable Shares
                        -------------
pursuant to a registration requested in accordance with Section 2 would result
in a substantial or insubstantial change of ownership transfer of control of the
Company or its FCC licenses requiring prior approval (as such concepts are
defined in the Communications Act and the rules and regulations of the FCC
adopted thereunder), then the Company shall promptly take all reasonable actions
deemed necessary by counsel to the Company to obtain from the FCC such consents
as may be necessary to permit such sale of such Registrable Shares.  The Company
shall begin to take such actions within 15 days after the date on which the
Company has received the last request for the registration of Registrable Shares
in any one transaction, file necessary applications within 30 days of such date,
and generally shall use all reasonable efforts to secure all necessary FCC
consent.  The selling Investors will provide reasonable assistance in connection
with the preparation and filing with the FCC of appropriate applications for
consent to any such transfer of control and obtaining such consent.

          SECTION 25.   SPECIFIC PERFORMANCE. The parties hereto recognize and
                        --------------------
agree that money damages may be insufficient to compensate the holders of any
Registrable Shares for breaches by the Company of the terms hereof and,
consequently, that the equitable remedy of specific performance of the terms
hereof will be available in the event of any such breach.


         [The remainder of this page has been intentionally left blank]

                                      -16-
<PAGE>

                                                 [Registration Rights Agreement]

       IN WITNESS WHEREOF, the Company and the Purchasers have caused this
Registration Rights Agreement to be executed as of the date first above written
by their respective officers thereunto duly authorized.



The Company:                  ADVANCED RADIO TELECOM CORP.


                              By: /s/ Henry C. Hirsch
                                  -------------------------------------------
                                  Name: Henry C. Hirsch
                                  Title:   Chairman and CEO


The Purchasers:               U.S. TELESOURCE, INC.

                              By: /s/ Marc B. Weisberg
                                  ------------------------------------------
                                  Name: Marc B. Weisberg
                                  Title:


                              OAK INVESTMENT PARTNERS VIII, LIMITED PARTNERSHIP

                              By:  Oak Associates VIII, LLC, General Partner

                              /s/ Bandel L. Carano
                              ----------------------------------------------
                              By:  Bandel L. Carano, Managing Member


                              OAK VIII AFFILIATE FUND, LIMITED PARTNERSHIP

                              By:  Oak VIII Affiliates, LLC, General Partner

                              /s/ Bandel L. Carano
                              ----------------------------------------------
                              By:  Bandel L. Carano, Managing Member



<PAGE>

                                                 [Registration Rights Agreement]

                              MERITECH CAPITAL PARTNERS

                              By:
                                 -----------------------------------------
                                  Name:
                                  Title:


<PAGE>

                                                 [Registration Rights Agreement]

                           ACCEL VI L.P.
                           BY: ACCEL VI ASSOCIATES L.L.C.
                           ITS GENERAL PARTNER

                           BY: /s/ G. Carter Sednaoui
                               ----------------------------------------
                               Managing Member


                           ACCEL INTERNET FUND II L.P.
                           BY: ACCEL INTERNET FUND II ASSOCIATES L.L.C.
                           ITS GENERAL PARTNER

                           BY: /s/ G. Carter Sednaoui
                               -------------------------------------
                               Managing Member


                           ACCEL KEIRETSU VI L.P.
                           BY: ACCEL KEIRETSU VI ASSOCIATES L.L.C.
                           ITS GENERAL PARTNER

                           By: /s/ G. Carter Sednaoui
                               ---------------------------------------
                               Managing Member


                           ACCEL INVESTORS '98 L.P.

                           By: /s/ G. Carter Sednaoui
                               ---------------------------------------
                               General Partner


<PAGE>

                                                 [Registration Rights Agreement]


                          BRENTWOOD ASSOCIATES IX, L.P.
                          By Brentwood IX Ventures, L.L.C.
                          Its General Partners

                          By:  /s/ John L. Walecka
                             --------------------------------
                             Name: John L. Walecka
                             Title:  Managing Member

                          BRENTWOOD AFFILIATES FUND III, L.P.
                          By Brentwood IX Ventures, L.L.C.
                          Its General Partner

                          By:  /s/ John L. Walecka
                             --------------------------------
                             Name: John L. Walecka
                             Title:  Managing Member



<PAGE>

                                                 [Registration Rights Agreement]

                          COLUMBIA CAPITAL ARTT INVESTORS, LLC
                          By:  Columbia Capital, L.L.C.
                          Its:   Managing Member


                          By: /s/ James B. Fleming, Jr.
                              -----------------------------------
                              Name:  James B. Fleming, Jr.
                              Title:    Managing Director


                          COLUMBIA CAPITAL ARTT PARTNERS, LLC
                          By:  Columbia Capital, L.L.C.
                          Its:   Managing Member


                          By: /s/ James B. Fleming, Jr.
                              -----------------------------------
                              Name:  James B. Fleming, Jr.
                             Title:    Managing Director


<PAGE>

                                                 [Registration Rights Agreement]

                         WORLDVIEW TECHNOLOGY PARTNERS II, L.P.
                         By: Worldview Capital II, L.P., General Partner
                         By: Worldview Equity I, L.L.C., General Partner

                         By: /s/ James Wei
                             ----------------------------------------------
                             Name:  James Wei
                             Title:  Member


                         WORLDVIEW TECHNOLOGY INTERNATIONAL II, L.P.
                         By: Worldview Capital II, L.P., General Partner
                         By: Worldview Equity I, L.L.C., General Partner

                         By: /s/ James Wei
                             ----------------------------------------------
                             Name:  James Wei
                             Title:  Member


                         WORLDVIEW STRATEGIC PARTNERS II, L.P.
                         By: Worldview Capital II, L.P., General Partner
                         By: Worldview Equity I, L.L.C., General Partner

                         By: /s/ James Wei
                             ----------------------------------------------
                             Name:  James Wei
                             Title:  Member


<PAGE>

                                                 [Registration Rights Agreement]

                        GLOBAL PRIVATE EQUITY II - EUROPE LIMITED PARTNERSHIP

                        GLOBAL PRIVATE EQUITY II - PGGM LIMITED PARTNERSHIP

                        DIGITAL MEDIA AND COMMUNICATIONS II LIMITED PARTNERSHIP

                        OAKSTONE VENTURES LIMITED PARTNERSHIP

                        ADVENT CROWN FUND II C.V.

                        ADWEST LIMITED PARTNERSHIP
                        By:  Advent International Limited Partnership, General
                             Partner
                        By:  Advent International Corporation, General Partner
                        By:  Andrew Fillat, Senior Vice President*

                        ADVENT GLOBAL GECC LIMITED PARTNERSHIP
                        By:  Advent Global Management Limited Partnership,
                             General Partner
                        By:  Advent International Limited Partnership,
                             General Partner
                        By:  Advent International Corporation, General Partner
                        By:  Andrew Fillat, Senior Vice President*

                        ADVENT PARTNERS LIMITED PARTNERSHIP
                        By:  Advent International Corporation, General Partner
                        By:  Andrew Fillat, Senior Vice President*

                        *For all of the above:

                        /s/ Andrew Fillat
                        ---------------------------------------------------
                        Andrew Fillat, Senior Vice President


<PAGE>

                                                 [Registration Rights Agreement]


                              BESSEMER VENTURE PARTNERS IV L.P.
                              By: Deer IV & Co. LLC, General Partner

                              By: /s/ Robert H. Buescher
                                  --------------------------------------
                                  Name:  Robert H. Buescher
                                  Title:  Manager


                              BESSEC VENTURES IV L.P.
                              By: Deer IV & Co. LLC, General Partner

                              By: /s/ Robert H. Buescher
                                  --------------------------------------
                                  Name:  Robert H. Buescher
                                  Title:  Manager


                              COVE VENTURES, LLC
                              By: Cove Road Associates, LLC, Managing Member

                              By: /s/ Robert Goodman
                                  --------------------------------------
                                  Name:  Robert Goodman
                                  Title:  Managing Member


<PAGE>

                                                 [Registration Rights Agreement]

                              ADAMS CAPITAL MANAGEMENT, L.P.
                              By: ACM Capital Partners II, L.P., General Partner
                              By: Joel P. Adams, General Partner

                              By: /s/ Joel P. Adams
                                  -------------------------------------------
                                  Name:  Joel P. Adams
                                  Title:  General Partner