ANNEX IV
                        TO SECURITIES PURCHASE AGREEMENT


                          REGISTRATION RIGHTS AGREEMENT

                  THIS REGISTRATION RIGHTS AGREEMENT, dated as of December 28,
1999 (this "Agreement"), is made by and between ADVANCED VIRAL RESEARCH CORP., a
Delaware corporation, with headquarters located at 200 Corporate Boulevard
South, Yonkers, NY 10701 (the "Company"), and each entity named on a signature
page hereto (each, an "Initial Investor") (each agreement with an Initial
Investor being deemed a separate and independent agreement between the Company
and such Initial Investor, except that each Initial Investor acknowledges and
consents to the rights granted to each other Initial Investor under such
agreement).

                              W I T N E S S E T H:

                  WHEREAS, upon the terms and subject to the conditions of the
Securities Purchase Agreement, dated as of December 28, 1999, between the
Initial Investor and the Company (the "Securities Purchase Agreement"; terms not
otherwise defined herein shall have the meanings ascribed to them in the
Securities Purchase Agreement), the Company has agreed to issue and sell to the
Initial Investor one or more 7% Convertible Debentures of the Company, in an
aggregate principal amount not exceeding $2,000,000 (the "Debentures"); and

                  WHEREAS, the Company has agreed to issue the Warrants to the
Initial Investor in connection with the issuance of the Debentures; and

                  WHEREAS, the Debentures are convertible into shares of Common
Stock (the "Conversion Shares"; which term, for purposes of this Agreement,
shall include shares of Common Stock of the Company issuable in lieu of accrued
interest on conversion as contemplated by the Debentures) upon the terms and
subject to the conditions contained in the Debentures and the Warrants may be
exercised for the purchase of shares of Common Stock (the "Warrant Shares") upon
the terms and conditions of the Warrants; and

                  WHEREAS, to induce the Initial Investor to execute and deliver
the Securities Purchase Agreement, the Company has agreed to provide certain
registration rights under the Securities Act of 1933, as amended, and the rules
and regulations thereunder, or any similar successor statute (collectively, the
"Securities Act"), with respect to the Conversion Shares and the Warrant Shares;


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                  NOW, THEREFORE, in consideration of the premises and the
mutual covenants contained herein and other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the Company and the
Initial Investor hereby agree as follows:

                  1. Definitions. As used in this Agreement, the following terms
shall have the following meanings:

                  (a) "Investor" means the Initial Investor and any permitted
transferee or assignee who agrees to become bound by the provisions of this
Agreement in accordance with Section 9 hereof and who holds Debentures, Warrants
or Registrable Securities.

                  (b) "Potential Material Event" means any of the following: (i)
the possession by the Company of material information not ripe for disclosure in
a registration statement, which shall be evidenced by determinations in good
faith by the Board of Directors of the Company that disclosure of such
information in the registration statement would be detrimental to the business
and affairs of the Company; or (ii) any material engagement or activity by the
Company which would, in the good faith determination of the Board of Directors
of the Company, be adversely affected by disclosure in a registration statement
at such time, which determination shall be accompanied by a good faith
determination by the Board of Directors of the Company that the registration
statement would be materially misleading absent the inclusion of such
information.

                  (c) "Register," "Registered," and "Registration" refer to a
registration effected by preparing and filing a Registration Statement or
Statements in compliance with the Securities Act and pursuant to Rule 415 under
the Securities Act or any successor rule providing for offering securities on a
continuous basis ("Rule 415"), and the declaration or ordering of effectiveness
of such Registration Statement by the United States Securities and Exchange
Commission (the "SEC").

                  (d) "Registrable Securities" means the Conversion Shares and
the Warrant Shares.

                  (e) "Registration Statement" means a registration statement of
the Company under the Securities Act.

                  (f) "Required Effective Date" means the relevant Initial
Required Effective Date or Increased Required Effective Date (as those terms are
defined below).

                  2.       Registration.

                  (a)      Mandatory Registration.

                  (i) The Company shall prepare and file with the SEC, as soon
as possible after the Initial Closing Date either a Registration Statement on
Form S-1or an amendment to an existing Registration Statement, in either event
registering for resale by the Investor a sufficient


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number of shares of Common Stock for the Initial Investors to sell the
Registrable Securities (or such lesser number as may be required by the SEC, but
in no event less than the aggregate number of shares equal to (A) two hundred
twenty-five percent (225%) of the number of shares into which the principal of
the Initial Debentures and the Additional Debentures would be convertible at the
time of filing of such Registration Statement (assuming for such purposes that
the Additional Debentures had been issued at such date and that all Debentures
had been eligible to be converted, and had been converted into Conversion Shares
in accordance with their terms, whether or not such issuance, eligibility or
conversion had in fact occurred as of such date) plus (B) the number of shares
which would be issued upon exercise of all of the Warrants (assuming for such
purposes that the Warrants issued in connection with the purchase and sale of
all Debentures, including on the Additional Closing Date, had been issued and
that all Warrants had been eligible to be exercised for the maximum number of
shares contemplated thereby and had been exercised in accordance with their
terms, whether or not such issuance, eligibility or exercise had in fact
occurred as of such date). The Registration Statement (W) shall include only the
Registrable Securities and the shares referred to in Exhibit 1 annexed hereto;
and (X) shall also state that, in accordance with Rule 416 and 457 under the
Securities Act, it also covers such indeterminate number of additional shares of
Common Stock as may become issuable upon conversion of the Debentures and the
exercise of the Warrants to prevent dilution resulting from stock splits, or
stock dividends. The Company will use its reasonable best efforts to cause such
Registration Statement to be declared effective on a date (the "Initial Required
Effective Date") which no later than is the earlier of (Y) five (5) days after
oral or written notice by the SEC that it may be declared effective or (Z)
ninety-five (95) days after the Initial Closing Date.

                  (ii) If at any time (an "Increased Registered Shares Date"),
the number of shares of Common Stock represented by the Registrable Shares,
issued or to be issued as contemplated by the Transaction Agreements, exceeds
the aggregate number of shares of Common Stock then registered, the Company
shall, within ten (10) business days after receipt of a written notice from any
Investor, either (X) amend the Registration Statement filed by the Company
pursuant to the preceding provisions of this Section 2, if such Registration
Statement has not been declared effective by the SEC at that time, to register,
in the aggregate, at least the number of shares equal to (A) the number of
shares (the "Increased Shares Amount") theretofore issued on conversion of the
Debentures (including any interest paid on conversion by the issuance of
Conversion Shares), plus (B) the sum of (I) two hundred twenty-five percent
(225%) of the number of shares into which the then unconverted Debentures would
be convertible at the time of relevant filing with the SEC or as of the
Increased Registered Shares Date, whichever is higher, plus (II) the number of
shares which would be issued upon exercise of all of the Warrants issued in
connection with the purchase and sale of the Debentures, in each case computed
as contemplated by the immediately preceding subparagraph (i), or (Y) if such
Registration Statement has been declared effective by the SEC at that time, file
with the SEC an additional Registration Statement on Form S-1 or other
appropriate registration statement form (an "Additional Registration Statement")
to register the number of shares equal to the excess of the Increased Shares
Amount over the aggregate number of shares of Common Stock already registered.
The Company will use its reasonable best efforts to cause such Registration
Statement to be declared effective on a date (each, an "Increased Required
Effective Date")


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which is no later than (Q) with respect to a Registration Statement under clause
(X) of this subparagraph (ii), the Initial Required Effective Date and (R) with
respect to an Additional Registration Statement, the earlier of (I) five (5)
days after notice by the SEC that it may be declared effective or (II)
seventy-five (75) days after the Increased Registered Shares Date.

                       (iii) The Initial Investor acknowledges that, without the
consent (the "Focus Consent") of Focus Investors LLC ("Focus"), the Company is
prohibited from filing a Registration Statement covering the Registrable
Securities with the SEC until a registration statement covering the resale of
the Company's Common Stock issuable upon conversion of a convertible debenture
and exercise of warrants held by Focus is declared effective by the SEC (the
"Focus Effective Date"). The Initial Investor agrees that, for purposes of
Section 2(a)(i) and Section 3(a) hereof, the failure by the Company to file a
Registration Statement covering the Registrable Securities prior to the Focus
Effective Date or prior to obtaining the Focus Consent , whichever is earlier,
shall not be deemed to be a failure to file such Registration Statement as soon
as possible after the Initial Closing Date or a failure to promptly file such
Registration Statement.

                  (b)      Payments by the Company.

                           (i) If the Registration Statement covering the
Registrable Securities is not effective by the relevant Required Effective Date
or if the Investor is restricted from making sales of Registrable Securities
covered by a previously effective Registration Statement at any time (the date
such restriction commences, a "Restricted Sale Date") after the Effective Date
other than during a Permitted Suspension Period (as defined below), then the
Company will make payments to the Initial Investor in such amounts and at such
times as shall be determined pursuant to this Section 2(b).

                           (ii) The amount (the "Periodic Amount") to be paid by
the Company to the Initial Investor shall be determined as of each Computation
Date (as defined below) and such amount shall be equal to the Periodic Amount
Percentage (as defined below) of the Purchase Price for all Debentures for the
period from the date following the relevant Required Effective Date or
Restricted Sale Date, as the case may be, to the first relevant Computation
Date, and thereafter to each subsequent Computation Date. The "Periodic Amount
Percentage" means (A) two percent (2.0%; except that, prior to the Effective
Date, it shall mean one and one-half percent [1.5%] )of the Purchase Price for
all the Debentures for the period from the date immediately following the
relevant Required Effective Date or Restricted Sale Date, as the case may be, to
the first or second relevant Computation Date and (B) two percent (2%) of the
Purchase Price of all Debentures to each Computation Date thereafter. Anything
in the preceding provisions of this paragraph (iii) to the contrary
notwithstanding, after the Effective Date the Purchase Price shall be deemed to
refer to the sum of (X) the principal amount of all Debentures not yet converted
and (Y) the Held Shares Value (as defined below). The "Held Shares Value" means,
for shares acquired by the Investor upon a conversion within the thirty (30)
days preceding the Restricted Sale Date, but not yet sold by the Investor, the
principal amount of the Debentures converted into such Conversion Shares;
provided, however, that if the Investor effected more than one

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conversion during such thirty (30) day period and sold less than all of such
shares, the sold shares shall be deemed to be derived first from the conversions
in the sequence of such conversions (that is, for example, until the number of
shares from the first of such conversions have been sold, all shares shall be
deemed to be from the first conversion; thereafter, from the second conversion
until all such shares are sold). By way of illustration and not in limitation of
the foregoing, if the Registration Statement is not declared effective until one
hundred seventy (170) days after the Initial Closing Date, the Periodic Amount
will aggregate five percent (5%) of the Purchase Price of the Debentures
theretofore issued (1.5% for days 96-125, plus 1.5% for days 126-155, plus 2%
for days 156-170).

                           (iii) Each Periodic Amount will be payable by the
Company in cash or other immediately available funds to the Investor monthly,
without requiring demand therefor by the Investor.

                           (iv) The parties acknowledge that the damages which
may be incurred by the Investor if the Registration Statement has not been
declared effective by a Required Effective Date, including if the right to sell
Registrable Securities under a previously effective Registration Statement is
suspended, may be difficult to ascertain. The parties agree that the Periodic
Amounts represent a reasonable estimate on the part of the parties, as of the
date of this Agreement, of the amount of such damages.

                           (v) Notwithstanding the foregoing, the amounts
payable by the Company pursuant to this provision shall not be payable to the
extent any delay in the effectiveness of the Registration Statement occurs
because of an act of, or a failure to act or to act timely by the Initial
Investor or its counsel, or in the event all of the Registrable Securities may
be sold pursuant to Rule 144 or another available exemption under the Act
without volume or other restrictions or limits.

                           (vii) "Computation Date" means (A) the date which is
the earlier of (1) thirty (30) days after any relevant Required Effective Date
or a Restricted Sale Date, as the case may be, or (2) the date after such
Required Effective Date or Restricted Sale Date on which the Registration
Statement is declared effective or has its restrictions removed, as the case may
be, and (B) each date which is the earlier of (1) thirty (30) days after the
previous Computation Date or (2) the date after the previous Computation Date on
which the Registration Statement is declared effective or has its restrictions
removed, as the case may be.

                  3. Obligations of the Company. In connection with the
registration of the Registrable Securities, the Company shall do each of the
following:

                  (a) Prepare promptly, and file with the SEC a Registration
Statement with respect to not less than the number of Registrable Securities
provided in Section 2(a) above, and thereafter use its reasonable best efforts
to cause such Registration Statement relating to Registrable Securities to
become effective by the Required Effective Date and keep the Registration
Statement effective at all times during the period (the "Registration Period")


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continuing until the earliest of (i) the date that is two (2) years after the
last day of the calendar month following the month in which the Effective Date
occurs, (ii) the date when the Investors may sell all Registrable Securities
under Rule 144 without volume or other restrictions or limits or (iii) the date
the Investors no longer own any of the Registrable Securities, which
Registration Statement (including any amendments or supplements thereto and
prospectuses contained therein) shall not contain any 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, in light of the circumstances in which
they were made, not misleading;

                  (b) Prepare and file with the SEC such amendments (including
post-effective amendments) and supplements to the Registration Statement and the
prospectus used in connection with the Registration Statement as may be
necessary to keep the Registration Statement effective at all times during the
Registration Period, and, during the Registration Period, comply with the
provisions of the Securities Act with respect to the disposition of all
Registrable Securities of the Company covered by the Registration Statement
until such time as all of such Registrable Securities have been disposed of in
accordance with the intended methods of disposition by the seller or sellers
thereof as set forth in the Registration Statement;

                  (c) Permit a single firm of counsel designated by the Initial
Investors to review the Registration Statement and all amendments and
supplements thereto a reasonable period of time (but not less than three (3)
business days) prior to their filing with the SEC, and not file any document in
a form to which such counsel reasonably objects;

                  (d) Notify each Investor, such Investor's legal counsel
identified to the Company and which has requested by written notice to the
Company that it receive such notification (which, until further notice, shall be
deemed to be Krieger & Prager LLP, Attn: Samuel Krieger, Esq., which firm has
requested to receive such notification; each, an "Investor's Counsel"), and any
managing underwriters immediately (and, in the case of (i)(A) below, not less
than two (2) business days prior to such filing) and (if requested by any such
Person) confirm such notice in writing no later than one (1) business day
following the day (i)(A) when a Prospectus or any Prospectus supplement or
post-effective amendment to the Registration Statement is proposed to be filed;
(B) whenever the SEC notifies the Company whether there will be a "review" of
such Registration Statement; (C) whenever the Company receives (or a
representative of the Company receives on its behalf) any oral or written
comments from the SEC in respect of a Registration Statement (copies or, in the
case of oral comments, summaries of such comments shall be promptly furnished by
the Company to the Investors); and (D) with respect to the Registration
Statement or any post-effective amendment, when the same has become effective;
(ii) of any request by the SEC or any other Federal or state governmental
authority for amendments or supplements to the Registration Statement or
Prospectus or for additional information; (iii) of the issuance by the SEC of
any stop order suspending the effectiveness of the Registration Statement
covering any or all of the Registrable Securities or the initiation of any
proceedings for that purpose; (iv) if at any time any of the representations or
warranties of the Company contained in any agreement (including any underwriting
agreement) contemplated hereby ceases to be true and correct in all material
respects; (v) of the receipt by the Company of any notification with respect

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to the suspension of the qualification or exemption from qualification of any of
the Registrable Securities for sale in any jurisdiction, or the initiation or
threatening of any proceeding for such purpose; and (vi) of the occurrence of
any event that to the best knowledge of the Company makes any statement made in
the Registration Statement or Prospectus or any document incorporated or deemed
to be incorporated therein by reference untrue in any material respect or that
requires any revisions to the Registration Statement, Prospectus or other
documents so that, in the case of the Registration Statement or the Prospectus,
as the case may be, it will not contain any untrue statement of a material fact
or omit to state any material fact required to be stated therein or necessary to
make the statements therein, in light of the circumstances under which they were
made, not misleading. In addition, the Company shall furnish the Investors with
copies of all intended written responses to the comments contemplated in clause
(C) of this Section 3(d) not later than one (1) business day in advance of the
filing of such responses with the SEC so that the Investors shall have the
opportunity to comment thereon;

                  (e) Furnish to each Investor and such Investor's Counsel (i)
promptly after the same is prepared and publicly distributed, filed with the
SEC, or received by the Company, one (1) copy of the Registration Statement,
each preliminary prospectus and prospectus, and each amendment or supplement
thereto, and (ii) such number of copies of a prospectus, and all amendments and
supplements thereto and such other documents, as such Investor may reasonably
request in order to facilitate the disposition of the Registrable Securities
owned by such Investor;

                  (f) As promptly as practicable after becoming aware thereof,
notify each Investor of the happening of any event of which the Company has
knowledge, as a result of which the prospectus included in the 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 statements therein, in light of the circumstances under which they were
made, not misleading, and use its best efforts promptly to prepare a supplement
or amendment to the Registration Statement or other appropriate filing with the
SEC to correct such untrue statement or omission, and deliver a number of copies
of such supplement or amendment to each Investor as such Investor may reasonably
request;

                  (g) As promptly as practicable after becoming aware thereof,
notify each Investor who holds Registrable Securities being sold (or, in the
event of an underwritten offering, the managing underwriters) of the issuance by
the SEC of a Notice of Effectiveness or any notice of effectiveness or any stop
order or other suspension of the effectiveness of the Registration Statement at
the earliest possible time;

                  (h) Notwithstanding the foregoing, if at any time or from time
to time after the date of effectiveness of the Registration Statement, the
Company notifies the Investors in writing of the existence of a Potential
Material Event, the Investors shall not offer or sell any Registrable
Securities, or engage in any other transaction involving or relating to the
Registrable Securities, from the time of the giving of notice with respect to a
Potential Material Event until such Investor receives written notice from the
Company that such Potential Material Event either has


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been disclosed to the public or no longer constitutes a Potential Material
Event; provided, however, that the Company may not so suspend the right to such
holders of Registrable Securities during the periods the Registration Statement
is required to be in effect other than during a Permitted Suspension Period. The
term "Permitted Suspension Period" means up to two suspension periods during any
consecutive 12-month period, each of which suspension period shall not either
(i) be for more than thirty (30) days or (ii) begin less than ten (10) business
days after the last day of the preceding suspension (whether or not such last
day was during or after a Permitted Suspension Period); provided further that
the Company shall, if lawful to do so, provide the Investor with at least two
(2) business days' notice of the existence (but not the substance of) a
Potential Material Event;

                  (i) Use its reasonable efforts to secure and maintain the
designation of all the Registrable Securities covered by the Registration
Statement on the "NASDAQ/Bulletin Board Market" of the National Association of
Securities Dealers Automated Quotations System ("NASDAQ") within the meaning of
Rule 11Aa2-1 of the SEC under the Securities Exchange Act of 1934, as amended
(the "Exchange Act"), and the quotation of the Registrable Securities on The
NASDAQ/Bulletin Board Market; and, without limiting the generality of the
foregoing, to arrange for at least two market makers to register with the
National Association of Securities Dealers, Inc. ("NASD") as such with respect
to such Registrable Securities;

                  (j) Provide a transfer agent and registrar, which may be a
single entity, for the Registrable Securities not later than the effective date
of the Registration Statement;

                  (k) Cooperate with the Investors who hold Registrable
Securities being offered to facilitate the timely preparation and delivery of
certificates for the Registrable Securities to be offered pursuant to the
Registration Statement and enable such certificates for the Registrable
Securities to be in such denominations or amounts as the case may be, as the
Investors may reasonably request, and, within three (3) business days after a
Registration Statement which includes Registrable Securities is ordered
effective by the SEC, the Company shall deliver, and shall cause legal counsel
selected by the Company to deliver, to the transfer agent for the Registrable
Securities (with copies to the Investors whose Registrable Securities are
included in such Registration Statement) an appropriate instruction and opinion
of such counsel; and

                  (l) Take all other reasonable actions necessary to expedite
and facilitate disposition by the Investor of the Registrable Securities
pursuant to the Registration Statement.

                  4. Obligations of the Investors. In connection with the
registration of the Registrable Securities, the Investors shall have the
following obligations:

                  (a) It shall be a condition precedent to the obligations of
the Company to complete the registration pursuant to this Agreement with respect
to the Registrable Securities of a particular Investor that such Investor shall
furnish to the Company such information regarding itself, the Registrable
Securities held by it, and the intended method of disposition of the Registrable
Securities held by it, as shall be reasonably required to effect the
registration of such

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Registrable Securities and shall execute such documents in connection with such
registration as the Company may reasonably request. At least ten (10) days prior
to the first anticipated filing date of the Registration Statement, the Company
shall notify each Investor of the information the Company requires from each
such Investor (the "Requested Information") if such Investor elects to have any
of such Investor's Registrable Securities included in the Registration
Statement. If at least two (2) business days prior to the filing date the
Company has not received the Requested Information from an Investor (a
"Non-Responsive Investor"), then the Company may file the Registration Statement
without including Registrable Securities of such Non-Responsive Investor;

                  (b) Each Investor, by such Investor's acceptance of the
Registrable Securities, agrees to cooperate with the Company as reasonably
requested by the Company in connection with the preparation and filing of the
Registration Statement hereunder, unless such Investor has notified the Company
in writing of such Investor's election to exclude all of such Investor's
Registrable Securities from the Registration Statement; and

                  (c) Each Investor agrees that, upon receipt of any notice from
the Company of the happening of any event of the kind described in Section 3(e)
or 3(f), above, such Investor will immediately discontinue disposition of
Registrable Securities pursuant to the Registration Statement covering such
Registrable Securities until such Investor's receipt of the copies of the
supplemented or amended prospectus contemplated by Section 3(e) or 3(f) and, if
so directed by the Company, such Investor shall deliver to the Company (at the
expense of the Company) or destroy (and deliver to the Company a certificate of
destruction) all copies in such Investor's possession, of the prospectus
covering such Registrable Securities current at the time of receipt of such
notice.

                  5. Expenses of Registration. All reasonable expenses (other
than underwriting discounts and commissions of the Investor) incurred in
connection with registrations, filings or qualifications pursuant to Section 3,
but including, without limitation, all registration, listing, and qualifications
fees, printers and accounting fees, the fees and disbursements of counsel for
the Company shall be borne by the Company. In addition, a fee for a single
counsel to review the Registration Statement on behalf of the Investors not
exceeding, in the aggregate for all Investors, $3,500, shall be borne by the
Company.

                  6. Indemnification. In the event any Registrable Securities
are included in a Registration Statement under this Agreement:

                  (a) To the extent permitted by law, the Company will indemnify
and hold harmless each Investor who holds such Registrable Securities, the
directors, if any, of such Investor, the officers, if any, of such Investor,
each person, if any, who controls any Investor within the meaning of the
Securities Act or the Exchange Act (each, an "Indemnified Person" or
"Indemnified Party"), against any losses, claims, damages, liabilities or
expenses (joint or several) incurred (collectively, "Claims") to which any of
them may become subject under the Securities Act, the Exchange Act or otherwise,
insofar as such Claims (or actions or proceedings,

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whether commenced or threatened, in respect thereof) arise out of or are based
upon any of the following statements, omissions or violations in the
Registration Statement, or any post-effective amendment thereof, or any
prospectus included therein: (i) any untrue statement or alleged untrue
statement of a material fact contained in the Registration Statement or any
post-effective amendment thereof or 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, (ii) any untrue statement or alleged untrue
statement of a material fact contained in the final prospectus (as amended or
supplemented, if the Company files any amendment thereof or supplement thereto
with the SEC) or the omission or alleged omission to state therein any material
fact necessary to make the statements made therein, in light of the
circumstances under which the statements therein were made, not misleading or
(iii) any violation or alleged violation by the Company of the Securities Act,
the Exchange Act, any state securities law or any rule or regulation under the
Securities Act, the Exchange Act or any state securities law (the matters in the
foregoing clauses (i) through (iii) being, collectively, "Violations"). Subject
to clause (b) of this Section 6, the Company shall reimburse the Investors,
promptly as such expenses are incurred and are due and payable, for any legal
fees or other reasonable expenses incurred by them in connection with
investigating or defending any such Claim. Notwithstanding anything to the
contrary contained herein, the indemnification agreement contained in this
Section 6(a) shall not (I) apply to a Claim arising out of or based upon a
Violation which occurs in reliance upon and in conformity with information
furnished in writing to the Company by or on behalf of any Indemnified Person
expressly for use in connection with the preparation of the Registration
Statement or any such amendment thereof or supplement thereto, after such
prospectus was made available by the Company pursuant to Section 3(c) hereof;
(II) be available to the extent such Claim is based on a failure of the Investor
to deliver or cause to be delivered the prospectus made available by the Company
or the amendment or supplement thereto made available by the Company; (III) be
available to the extent such Claim is based on the delivery of a prospectus by
the Investor after receiving notice from the Company under Section 3(e), (f) or
(g) hereof (other than a notice regarding the effectiveness of the Registration
Statement or any amendment or supplement thereto), or (IV) apply to amounts paid
in settlement of any Claim if such settlement is effected without the prior
written consent of the Company, which consent shall not be unreasonably withheld
or delayed. Each Investor will indemnify the Company and its officers, directors
and agents (each, an "Indemnified Person" or "Indemnified Party") against any
claims arising out of or based upon a Violation which occurs in reliance upon
and in conformity with information furnished in writing to the Company, by or on
behalf of such Investor, expressly for use in connection with the preparation of
the Registration Statement or the amendment or supplement thereto, subject to
such limitations and conditions as are applicable to the Indemnification
provided by the Company to this Section 6. Such indemnity shall remain in full
force and effect regardless of any investigation made by or on behalf of the
Indemnified Person and shall survive the transfer of the Registrable Securities
by the Investors pursuant to Section 9.

                  (b) Promptly after receipt by an Indemnified Person or
Indemnified Party under this Section 6 of notice of the commencement of any
action (including any governmental action), such Indemnified Person or
Indemnified Party shall, if a Claim in respect thereof is to be made against any
indemnifying party under this Section 6, deliver to the indemnifying party a

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written notice of the commencement thereof and the indemnifying party shall have
the right to participate in, and, to the extent the indemnifying party so
desires, jointly with any other indemnifying party similarly noticed, to assume
control of the defense thereof with counsel mutually satisfactory to the
indemnifying party and the Indemnified Person or the Indemnified Party, as the
case may be. In case any such action is brought against any Indemnified Person
or Indemnified Party, and it notifies the indemnifying party of the commencement
thereof, the indemnifying party will be entitled to participate in, and, to the
extent that it may wish, jointly with any other indemnifying party similarly
notified, assume the defense thereof, subject to the provisions herein stated
and after notice from the indemnifying party to such Indemnified Person or
Indemnified Party of its election so to assume the defense thereof, the
indemnifying party will not be liable to such Indemnified Person or Indemnified
Party under this Section 6 for any legal or other reasonable out-of-pocket
expenses subsequently incurred by such Indemnified Person or Indemnified Party
in connection with the defense thereof other than reasonable costs of
investigation, unless the indemnifying party shall not pursue the action of its
final conclusion. The Indemnified Person or Indemnified Party shall have the
right to employ separate counsel in any such action and to participate in the
defense thereof, but the fees and reasonable out-of-pocket expenses of such
counsel shall not be at the expense of the indemnifying party if the
indemnifying party has assumed the defense of the action with counsel reasonably
satisfactory to the Indemnified Person or Indemnified Party provided such
counsel is of the opinion that all defenses available to the Indemnified Party
can be maintained without prejudicing the rights of the indemnifying party. The
failure to deliver written notice to the indemnifying party within a reasonable
time of the commencement of any such action shall not relieve such indemnifying
party of any liability to the Indemnified Person or Indemnified Party under this
Section 6, except to the extent that the indemnifying party is prejudiced in its
ability to defend such action. The indemnification required by this Section 6
shall be made by periodic payments of the amount thereof during the course of
the investigation or defense, as such expense, loss, damage or liability is
incurred and is due and payable.

                  7. Contribution. To the extent any indemnification by an
indemnifying party is prohibited or limited by law, the indemnifying party
agrees to make the maximum contribution with respect to any amounts for which it
would otherwise be liable under Section 6 to the fullest extent permitted by
law; provided, however, that (a) no contribution shall be made under
circumstances where the maker would not have been liable for indemnification
under the fault standards set forth in Section 6; (b) no seller of Registrable
Securities guilty of fraudulent misrepresentation (within the meaning of Section
11(f) of the Securities Act) shall be entitled to contribution from any seller
of Registrable Securities who was not guilty of such fraudulent
misrepresentation; and (c) except where the seller has committed fraud (other
than a fraud by reason of the information included or omitted from the
Registration Statement as to which the Company has not given notice as
contemplated under Section 3 hereof) or intentional misconduct, contribution by
any seller of Registrable Securities shall be limited in amount to the net
amount of proceeds received by such seller from the sale of such Registrable
Securities.

                  8. Reports under Exchange Act. With a view to making available
to the Investors the benefits of Rule 144 promulgated under the Securities Act
or any other similar rule

                                       11
<PAGE>

or regulation of the SEC that may at any time permit the Investors to sell
securities of the Company to the public without registration ("Rule 144"), the
Company agrees to:

                  (a) make and keep public information available, as those terms
are understood and defined in Rule 144;

                  (b) file with the SEC in a timely manner all reports and other
documents required of the Company under the Securities Act and the Exchange Act;
and

                  (c) furnish to each Investor so long as such Investor owns
Registrable Securities, promptly upon request, (i) a written statement by the
Company that it has complied with the reporting requirements of Rule 144, the
Securities Act and the Exchange Act, (ii) a copy of the most recent annual or
quarterly report of the Company and such other reports and documents so filed by
the Company and (iii) such other information as may be reasonably requested to
permit the Investors to sell such securities pursuant to Rule 144 without
registration.

                  9. Assignment of the Registration Rights. The rights to have
the Company register Registrable Securities pursuant to this Agreement shall be
automatically assigned by the Investors to any transferee of the Registrable
Securities (or all or any portion of any unconverted Debenture or unexercised
Warrant) only if: (a) the Investor agrees in writing with the transferee or
assignee to assign such rights, and a copy of such agreement is furnished to the
Company within a reasonable time after such assignment, (b) the Company is,
within a reasonable time after such transfer or assignment, furnished with
written notice of (i) the name and address of such transferee or assignee and
(ii) the securities with respect to which such registration rights are being
transferred or assigned, (c) immediately following such transfer or assignment
the further disposition of such securities by the transferee or assignee is
restricted under the Securities Act and applicable state securities laws, and
(d) at or before the time the Company received the written notice contemplated
by clause (b) of this sentence the transferee or assignee agrees in writing with
the Company to be bound by all of the provisions contained herein. In the event
of any delay in filing or effectiveness of the Registration Statement as a
result of such assignment, the Company shall not be liable for any damages
arising from such delay, or the payments set forth in Section 2(c) hereof
arising from such delay.

                  10. Amendment of Registration Rights. Any provision of this
Agreement may be amended and the observance thereof may be waived (either
generally or in a particular instance and either retroactively or
prospectively), only with the written consent of the Company and Investors who
hold an sixty-seven (67%) percent interest of the Registrable Securities. Any
amendment or waiver effected in accordance with this Section 10 shall be binding
upon each Investor and the Company.

                  11.      Miscellaneous.

                  (a) A person or entity is deemed to be a holder of Registrable
Securities whenever such person or entity owns of record such Registrable
Securities. If the Company

                                       12

<PAGE>

receives conflicting instructions, notices or elections from two or more persons
or entities with respect to the same Registrable Securities, the Company shall
act upon the basis of instructions, notice or election received from the
registered owner of such Registrable Securities.

                  (b) Notices required or permitted to be given hereunder shall
be given in the manner contemplated by the Agreement, (i) if to the Company or
to the Initial Investor, to their respective address contemplated by the
Agreement, and (iii) if to any other Investor, at such address as such Investor
shall have provided in writing to the Company, or at such other address as each
such party furnishes by notice given in accordance with this Section 11(b).

                  (c) Failure of any party to exercise any right or remedy under
this Agreement or otherwise, or delay by a party in exercising such right or
remedy, shall not operate as a waiver thereof.

                  (d) This Agreement shall be governed by and interpreted in
accordance with the laws of the State of New York for contracts to be wholly
performed in such state and without giving effect to the principles thereof
regarding the conflict of laws. Each of the parties consents to the jurisdiction
of the federal courts whose districts encompass any part of the City of New York
or the state courts of the State of New York sitting in the City of New York in
connection with any dispute arising under this Agreement and hereby waives, to
the maximum extent permitted by law, any objection, including any objection
based on forum non coveniens, to the bringing of any such proceeding in such
jurisdictions. To the extent determined by such court, the Company shall
reimburse the Buyer for any reasonable legal fees and disbursements incurred by
the Buyer in enforcement of or protection of any of its rights under this
Agreement.

                  (e) If any provision of this Agreement shall be invalid or
unenforceable in any jurisdiction, such invalidity or unenforceability shall not
affect the validity or enforceability of the remainder of this Agreement or the
validity or enforceability of this Agreement in any other jurisdiction.

                  (f) Subject to the requirements of Section 9 hereof, this
Agreement shall inure to the benefit of and be binding upon the successors and
assigns of each of the parties hereto.

                  (g) All pronouns and any variations thereof refer to the
masculine, feminine or neuter, singular or plural, as the context may require.

                  (h) The headings in this Agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning thereof.

                  (i) This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original but all of which shall
constitute one and the same agreement. This Agreement, once executed by a party,
may be delivered to the other party hereto by telephone line facsimile
transmission of a copy of this Agreement bearing the signature of the party so
delivering this Agreement.

                                       13
<PAGE>

                  (j) The Company acknowledges that any failure by the Company
to perform its obligations under Section 3(a) hereof, or any delay in such
performance could result in loss to the Investors, and the Company agrees that,
in addition to any other liability the Company may have by reason of such
failure or delay, the Company shall be liable for all direct damages caused by
any such failure or delay, unless the same is the result of force majeure.
Neither party shall be liable for consequential damages.

                  (k) This Agreement constitutes the entire agreement among the
parties hereto with respect to the subject matter hereof. There are no
restrictions, promises, warranties or undertakings, other than those set forth
or referred to herein. This Agreement supersedes all prior agreements and
understandings among the parties hereto with respect to the subject matter
hereof. This Agreement may be amended only by an instrument in writing signed by
the party to be charged with enforcement thereof.


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                                       14

<PAGE>

                  IN WITNESS WHEREOF, the parties have caused this Agreement to
be duly executed by their respective officers thereunto duly authorized as of
the day and year first above written.


                                    COMPANY:
                                    ADVANCED VIRAL RESEARCH CORP.

                                    By:    /s/ Shalom Z. Hirschman
                                    -------------------------------------------
                                           Shalom Z. Hirschman
                                    Title: President and Chief Executive Officer



                                    INITIAL INVESTOR:

                                    ENDEAVOUR CAPITAL FUND S.A.

                                    By:      /s/ Shamuli Margulies
                                    -------------------------------------------
                                    Name:    Shamuli Margulies
                                    Title:   Director
                                           -----------------------