REGISTRATION RIGHTS AGREEMENT


THIS REGISTRATION RIGHTS AGREEMENT (as amended, restated, supplemented or
otherwise modified from time to time, this "AGREEMENT") is entered into as of
this 30th day of October, 2001 by and between ALLION HEALTHCARE, INC., a
Delaware corporation (together with its successors and assigns, the
"CORPORATION"), and Gainesborough, L.L.C. (together with its successors and
assigns, the "Securityholder").

                                    RECITALS

WHEREAS, the Corporation and the Securityholder have entered into that certain
Series B Convertible Preferred Stock Purchase Agreement, dated as of October __,
2001 (as amended, restated, supplemented or otherwise modified from time to
time, the "PURCHASE AGREEMENT"), pursuant to which the Securityholder has
agreed, INTER ALIA, to purchase, and the Corporation has agreed, INTER ALIA, to
issue and sell to the Securityholder, certain shares of Series B Preferred Stock
(as defined below);

WHEREAS, the Corporation and the Securityholder deem it in their respective best
interests to provide for certain arrangements with respect to the registration
of shares of Common Stock (as defined below) under the United States Securities
Act of 1933, as amended (the "SECURITIES ACT"); and

WHEREAS, the execution and delivery of this Agreement is a condition precedent
to the consummation of the transactions contemplated by the Purchase Agreement.

NOW, THEREFORE, in consideration of the premises and the mutual covenants and
obligations hereinafter set forth and other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto,
intending to be legally bound, hereby agree as follows:

SECTION 1. DEFINITIONS. (a) As used herein, each of the following terms shall
have the meaning set forth or referred to below:

"AFFILIATE" shall mean (i) with respect to any individual, (A) a spouse or first
generation descendant of such individual and (B) any trust, limited liability
company or family partnership whose beneficiaries shall solely be such
individual and/or such individual's spouse and/or any other individual related
to the first degree by blood or adoption to such individual or such individual's
spouse and (ii) with respect to any Person which is not an individual, a
director, officer, general partner or managing member of such Person, and any
other Person that, directly or indirectly through one or more intermediaries
Controls, is Controlled by, or is under common Control with, such Person. For
purposes hereof, "CONTROL" (including, with correlative meanings, the terms
"CONTROLLING," "CONTROLLED BY" and "UNDER COMMON CONTROL WITH"), as applied to
any Person, means the possession, directly or indirectly, of the power to direct
or cause the direction of the management and policies of such Person, whether
through the ownership of voting securities, by contract or otherwise.


                                       -1-
<PAGE>


"AGREEMENT" shall have the meaning set forth in the first paragraph of this
agreement.

"BUSINESS DAY" shall mean any day that is not a Saturday, Sunday or legal
holiday on which banking institutions in the State of New York are authorized or
obligated to close.

"COMMON STOCK" shall mean the common stock, par value $0.001 per share, of the
Corporation, as constituted on the date hereof, and any stock into which such
Common Stock shall have been changed or any stock resulting from any
recapitalization, reorganization, merger, sale of assets or reclassification.

"CORPORATION" shall have the meaning set forth in the first paragraph of this
Agreement.

"DELAY PERIOD" shall have the meaning set forth in Section 2(d) hereof.

"DEMAND NOTICE" shall have the meaning set forth in Section 2(a) hereof.

"DEMAND REGISTRATION" shall have the meaning set forth in Section 2(a) hereof.

"EXCHANGE ACT" shall mean the United States Securities Exchange Act of 1934, as
amended.

"HOLD BACK PERIOD" shall have the meaning set forth in Section 4(a) hereof.

"HOLDER" or "HOLDERS" shall mean the Securityholder and/or any successors
thereto or assignees or transferees thereof who or which comply with the second
sentence of Section 10 hereof.

"INSPECTORS" shall have the meaning set forth in Section 5(j) hereof.

"INTERRUPTION PERIOD" shall have the meaning set forth in Section 5(k) hereof.

"LOSSES" shall have the meaning set forth in Section 8(a) hereof.

"NASD" shall mean the National Association of Securities Dealers, Inc., or any
successor thereof.

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

"PERSON" shall mean any natural person, corporation, limited partnership,
limited liability company, general partnership, joint stock company, joint
venture, association, company, trust, bank, trust company, land trust, business
trust or other organization whether or not a legal entity, and any government or
agency or political subdivision thereof.

"PIGGYBACK REGISTRATION" shall have the meaning set forth in Section 3(a)
hereof.

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

"PROSPECTUS" shall mean the prospectus included in any Registration Statement
(including a prospectus that discloses information previously omitted from a
prospectus filed as part of an effective registration statement in reliance upon
Rule 430A under the Securities Act), as amended or supplemented by any
prospectus supplement with respect to the terms of the offering of any portion
of the Registrable Shares covered by such Registration Statement and all other
amendments and supplements to such prospectus, including post-effective
amendments, and all material incorporated by reference or deemed to be
incorporated by reference in such prospectus.


                                       -2-
<PAGE>


"PURCHASE AGREEMENT" shall have the meaning set forth in the first recital to
this Agreement.

"RECORDS" shall have the meaning set forth in Section 5(j) hereof.

"REGISTRABLE SHARES" shall mean, at any time, with respect to any Holder (i) any
Shares and (ii) any other securities issued and issuable with respect to any
such Shares or the Series B Preferred Stock by way of a stock dividend, stock
distribution or stock split or in connection with a combination of shares,
recapitalization, merger, consolidation, sale of assets or other reorganization,
in each case in clauses (i) and (ii) which at any time are held by Holders (it
being understood that, for purposes of this Agreement, a Person shall be deemed
to be a holder of Registrable Shares whenever such Person has the right to
acquire or obtain from the Corporation any Registrable Shares, whether or not
such acquisition has actually been effected), if and so long as (x) such Shares
have not been sold to or through a broker or dealer or underwriter in a public
distribution or a public securities transaction and (y) such Shares have not
been sold in a transaction exempt from the registration and prospectus delivery
requirements of the Securities Act under Section 4(1) thereof so that all
transfer restrictions and restrictive legends with respect to such Shares are
removed upon the consummation of such sale and the seller and purchaser of such
shares of Common Stock shall have received an opinion of counsel for the
Corporation, which shall be in form and content reasonably satisfactory to the
seller and purchaser and their respective counsel, to the effect that such
Shares in the hands of the purchaser are freely transferable without restriction
or registration under the Securities Act in any public or private transaction.

"REGISTRATION" shall mean registration under the Securities Act of an offering
of Registrable Shares pursuant to a Demand Registration or a Piggyback
Registration.

"REGISTRATION STATEMENT" shall mean any registration statement of the
Corporation under the Securities Act that covers any of the Registrable Shares
pursuant to the provisions of this Agreement, including the related Prospectus,
all amendments and supplements to such registration statement (including pre-
and post-effective amendments), all exhibits thereto and all material
incorporated by reference or deemed to be incorporated by reference in such
registration statement.

"SEC" shall mean the United States Securities and Exchange Commission, or any
successor thereof.

"SECURITIES ACT" shall have the meaning set forth in the second recital to this
Agreement.

"SECURITYHOLDER" shall have the meaning set forth in the first paragraph of this
Agreement.

"SERIES A PREFERRED STOCK" shall mean the Series A Convertible Preferred Stock
of the Corporation.


                                      -3-
<PAGE>


"SERIES B PREFERRED STOCK" shall mean the Series B Convertible Preferred Stock
of the Corporation.

"SHARES" shall mean shares of Common Stock, including, without limitation, the
shares issuable upon conversion of the Series A Preferred Stock or the Series B
Preferred Stock and shares purchased or purchasable pursuant to the exercise of
any outstanding warrants options of the Company (or any portion thereof).

"UNDERWRITTEN OFFERING" shall mean a registration under the Securities Act in
which securities of the Corporation are sold to an underwriter for reoffering to
the public.

     (b) Words used herein, regardless of the number and gender specifically
     used, shall be deemed and construed to include any other number, singular
     or plural, and any other gender, masculine, feminine or neuter, as the
     context requires. The word "OR" is not exclusive and the word "INCLUDING"
     means "including without limitation." Unless otherwise specified, all
     accounting terms used in this Agreement shall be interpreted in accordance
     with generally accepted accounting principles in the United States as in
     effect from time to time, applied on a consistent basis.

SECTION 2. DEMAND REGISTRATION. (a) At any time and from time to time after the
one year anniversary of the Purchase Agreement, the Holders of a majority in
number of the Registrable Shares shall have the right, by written notice (the
"DEMAND NOTICE") given to the Corporation, to request the Corporation to
register (a "DEMAND REGISTRATION") under and in accordance with the provisions
of the Securities Act all or any portion of such Holders' Registrable Shares.
Upon receipt of any such Demand Notice, the Corporation shall promptly, but in
no event more than five (5) business days after receipt thereof, notify each
other Holder of the receipt of such Demand Notice and, subject to the
limitations set forth below, shall include in the proposed registration all
Registrable Shares with respect to which the Corporation has received written
requests for inclusion therein within 30 days after delivery of the
Corporation's notice. In connection with any Demand Registration in which more
than one Holder or holders of Other Shares or the Corporation participates, in
the event that such Demand Registration involves an underwritten offering and
the managing underwriter or underwriters participating in such offering advise
in writing the Holders of Registrable Shares to be included in such offering
that the total amount of Shares to be included in such offering exceeds the
amount that can be sold in (or during the time of) such offering without
delaying or jeopardizing the success of such offering (including the price per
share of the Shares to be sold), then the number of Registrable Shares, Primary
Shares and Other Shares (which have registration rights with respect to such
offering) shall be reduced on a pro rata basis (based upon the number of shares
requested or proposed to be registered by each such holder and the Corporation)
to a number deemed satisfactory by such managing underwriter or underwriters,
provided, that the securities to be excluded shall be determined in the sequence
reflected in Section 3(b)(A). The Holders as a group shall be entitled to one
Demand Registration on each of Form S-1, Form S-2 and Form S-3 (or any successor
form thereto); PROVIDED, that any Demand Registration that does not become
effective or is not maintained for the time period required in accordance with
Section 2(c) hereof shall not count as one of such Demand Registrations.



                                      -4-
<PAGE>


     (b) The Corporation shall as soon as practicable, but in no event more than
     90 days after the date on which the Corporation receives a Demand Notice
     given by the Holders in accordance with Section 2(a) hereof, file with the
     SEC, and the Corporation shall thereafter use its best efforts to cause to
     be declared effective within 180 days following the date the Corporation
     receives such Demand Notice, a Registration Statement on the appropriate
     form for the registration and sale, in accordance with the intended method
     or methods of distribution, of the total number of Registrable Shares
     specified by the Holders in such Demand Notice together with any other
     Registrable Shares with respect to which the Corporation has received a
     written request for inclusion in accordance with Section 2(a) hereof,
     subject to reduction as set forth in Section 2(a) hereof.

     (c) The Corporation shall use best efforts to keep each Registration
     Statement filed pursuant to this Section 2 continuously effective and
     usable for the resale of the Registrable Shares covered thereby for a
     period of 180 days from the date on which the SEC declares such
     Registration Statement effective, as such period may be extended pursuant
     to this Section 2, or if shorter, until all the Registrable Shares covered
     by such Registration Statement have been sold pursuant to such Registration
     Statement.

     (d) The Corporation shall be entitled to postpone the filing of any
     Registration Statement otherwise required to be prepared and filed by the
     Corporation pursuant to this Section 2, or suspend the use of any effective
     Registration Statement under this Section 2, for a reasonable period of
     time which shall be as short as practicable, but in any event not in excess
     of 60 days (a "DELAY PERIOD"), if the Corporation determines in good faith
     that the registration and distribution of the Registrable Shares covered or
     to be covered by such Registration Statement would materially interfere
     with any pending material financing, acquisition, disposition or corporate
     reorganization or other material corporate development involving the
     Corporation or any of its subsidiaries or would require premature
     disclosure thereof and promptly gives the Holders written notice of such
     determination, containing a statement of the reasons for such postponement
     and an approximation of the period of the anticipated delay; PROVIDED,
     HOWEVER, that (i) the aggregate number of days included in all Delay
     Periods during any consecutive 12 months shall not exceed the aggregate of
     (x) 120 days minus (y) the number of days occurring during all Hold Back
     Periods and Interruption Periods during such consecutive 12 months and (ii)
     a period of at least 60 days shall elapse between the termination of any
     Delay Period, Hold Back Period or Interruption Period and the commencement
     of the immediately succeeding Delay Period. If the Corporation shall so
     postpone the filing of a Registration Statement, the Holders of Registrable
     Shares to be registered shall have the right to withdraw the request for
     registration by written notice given by the Holders of a majority of the
     Registrable Shares that were to be registered to the Corporation within 45
     days after receipt of the notice of postponement or, if earlier, the
     termination of such Delay Period. The time period for which the Corporation
     is required to maintain the effectiveness of any Registration Statement
     shall be extended by the aggregate number of days of all Delay Periods, all
     Hold Back Periods and all Interruption Periods occurring during such
     Registration. The Corporation shall not be entitled to initiate a Delay
     Period unless it shall (A) concurrently prohibit sales by other
     securityholders under registration statements covering securities held by
     such other securityholders and (B) forbid purchases and sales in the open
     market by all officers and executives of the Corporation.


                                      -5-
<PAGE>


     (e) The Holders of a majority in number of the Registrable Shares to be
     included in a Registration Statement pursuant to this Section 2 may, at any
     time prior to the effective date of the Registration Statement relating to
     such Demand Registration, revoke such request by providing a written notice
     to the Corporation revoking such request, in which case such request will
     not count, except as provided below, towards the quota of Demand
     Registrations to which the Holders are entitled pursuant to this Agreement.
     In the event of such revocation, the Holders of the Registrable Shares to
     be included in such Demand Registration shall reimburse the Corporation for
     their PRO RATA share (based upon the number of Shares requested or proposed
     to be registered in such Registration) of the out-of-pocket registration
     expenses referred to in Section 6 hereof incurred by the Corporation in
     connection with the preparation, filing and processing of the Registration
     Statement, unless (i) there has been a material adverse change in the
     business, assets, properties, condition (financial or other) or results of
     operations of the Corporation and its subsidiaries taken as a whole, since
     the time of the Demand Notice, (ii) such revocation was based on the
     Corporation's failure to comply in any material respect with its
     obligations hereunder or (iii) the Holders of a majority in number of the
     Registrable Shares to be included in such Demand Registration choose to
     count the Demand Registration as one of the Demand Registrations to which
     the Holders are entitled pursuant to this Agreement.

SECTION 3. PIGGYBACK REGISTRATION. (a) If at any time the Corporation proposes
to file a registration statement under the Securities Act with respect to a
public offering of Shares for its own account (other than a registration
statement (i) on Form S-8 or any successor form thereto, (ii) filed solely in
connection with a dividend reinvestment plan or employee benefit plan covering
officers or directors of the Corporation or its Affiliates or (iii) on Form S-4
or any successor form thereto, in connection with a merger, acquisition,
exchange offer or similar corporate transaction) or for the account of any
holder of Shares, then the Corporation shall give written notice of such
proposed filing to each Holder at least 30 days before the anticipated filing
date. Such notice shall offer the Holders the opportunity to register such
amount of Registrable Shares as they may request (a "PIGGYBACK REGISTRATION").
Subject to Section 3(b) hereof, the Corporation shall include in each such
Piggyback Registration all Registrable Shares with respect to which the
Corporation has received written requests for inclusion therein within 20 days
after such notice has been given to the Holders. Each Holder shall be permitted
to withdraw all or any portion of the Registrable Shares of such Holder from a
Piggyback Registration at any time prior to the effective date of such Piggyback
Registration. The Holders shall be entitled to an unlimited number of Piggyback
Registrations.

     (b) The Corporation shall permit the Holders to include all such
     Registrable Shares on the same terms and conditions as the Shares, if any,
     of the Corporation included therein. Notwithstanding the foregoing, in the
     event that any Piggyback Registration involves an underwritten offering and
     the managing underwriter or underwriters participating in such offering
     advise in writing the Holders requesting registration that the total amount
     of securities requested to be included in such Piggyback Registration
     exceeds the amount which can be sold in (or during the time of) such
     offering without delaying or jeopardizing the success of the offering
     (including the price per share of the securities to be sold), then the
     number of Primary Shares, Registrable Shares and Other Shares (which have
     registration rights with respect to such offering) requested or proposed to
     be registered in such offering shall be reduced to a number deemed
     satisfactory by such managing underwriter or underwriters, PROVIDED, that
     the securities to be excluded shall be determined in the following
     sequence:


                                      -6-
<PAGE>


         (A) in the event the offering was proposed by or for the account of any
         holder of Shares: (i) FIRST, the Primary Shares; and (ii) SECOND, the
         Other Shares and the Registrable Shares on a PRO RATA basis (based upon
         the number of Shares requested to be registered by each such holder);

         (B) in the event the offering was proposed by or for the account of the
         Corporation: (i) FIRST, the Other Shares and the Registrable Shares on
         a PRO RATA basis (based upon the number of Shares requested to be
         registered by each such holder); and (ii) SECOND, the Primary Shares.

     (c) Nothing in this Agreement shall create any liability on the part of the
     Corporation to the Holders if the Corporation in its sole discretion should
     decide not to file a Registration Statement proposed to be filed pursuant
     to Section 3(a) hereof or to withdraw such Registration Statement
     subsequent to its filing, regardless of any action whatsoever that a Holder
     may have taken, whether as a result of the issuance by the Corporation of
     any notice hereunder or otherwise.

SECTION 4. HOLDBACK AGREEMENT. (a) If (x) the Corporation shall file a
Registration Statement (other than a registration statement (i) on Form S-8 or
any successor form thereto, (ii) filed solely in connection with a dividend
reinvestment plan or employee benefit plan covering officers or directors of the
Corporation or its Affiliates or (iii) on Form S-4 or any successor form
thereto, in connection with a merger, acquisition, exchange offer or similar
corporate transaction) with respect to an underwritten offering of Shares or
similar securities or securities convertible into, or exchangeable or
exercisable for, such securities and (y) with reasonable prior notice, the
managing underwriter or underwriters advise the Corporation in writing (in which
case the Corporation shall notify the Holders with a copy of such underwriter's
notice) that a public sale or distribution of Registrable Shares would
materially adversely affect such offering, then, each Holder shall, to the
extent not inconsistent with applicable law and unless such managing underwriter
or underwriters otherwise agree, refrain from, directly or indirectly, effecting
any public sale, distribution or short sale of any Registrable Shares (except as
part of such underwritten offering) during the period beginning ten days prior
to the effective date of such Registration Statement and continuing until the
earliest of (A) the abandonment of such offering, (B) such period of time as is
sufficient and appropriate in the opinion of the managing underwriter or
underwriters in order to complete the sale and distribution of securities
included in such registration (but in no event in excess of 90 days following
the effective date of any offering) and (C) the termination in whole or in part
of any "hold back" period obtained by the underwriter or underwriters in such
offering from the Corporation in connection therewith (each such period, a "HOLD
BACK PERIOD"); PROVIDED, that the Holders shall not be subject to the
restrictions contained in this Section 4(a) unless each officer and director of
the Corporation (regardless of the number of Shares then owned by such officer
or director) and each beneficial owner (as defined in Rule 13d-3 under the
Exchange Act) of at least 5% of the issued and outstanding shares of Common
Stock also agree to be bound by such restrictions.



                                      -7-
<PAGE>


     (b) If (x) the Corporation shall file a Registration Statement (other than
     a registration statement (i) on Form S-8 or any successor form thereto,
     (ii) filed solely in connection with a dividend reinvestment plan or
     employee benefit plan covering officers or directors of the Corporation or
     its Affiliates or (iii) on Form S-4 or any successor form thereto, in
     connection with a merger, acquisition, exchange offer or similar corporate
     transaction) with respect to an underwritten offering of Shares or similar
     securities or securities convertible into, or exchangeable or exercisable
     for, such securities and (y) with reasonable prior notice, the managing
     underwriter or underwriters advise the Corporation in writing (in which
     case the Corporation shall notify the Holders with a copy of such
     underwriter's notice) that a public sale or distribution of securities of
     the Corporation would materially adversely affect such offering, then, the
     Corporation shall, to the extent not inconsistent with applicable law and
     unless such managing underwriter or underwriters otherwise agree, refrain
     from, directly or indirectly, effecting any public sale, distribution or
     short sale of any securities of the Corporation (except as part of such
     underwritten offering) during the applicable Hold Back Period.

SECTION 5. REGISTRATION PROCEDURES. In connection with the registration
obligations of the Corporation pursuant to and in accordance with Sections 2 and
3 hereof (and subject to Sections 2 and 3 hereof), the Corporation shall use
reasonable best efforts to effect such registration to permit the sale of such
Registrable Shares in accordance with the intended method or methods of
disposition thereof, and pursuant thereto the Corporation shall as expeditiously
as possible (but subject to Sections 2 and 3 hereof):

     (a) prepare and file with the SEC a Registration Statement for the sale of
     the Registrable Shares on any form for which the Corporation then qualifies
     or which counsel for the Corporation shall deem appropriate, in accordance
     with such Holders' intended method or methods of distribution thereof,
     subject to Section 2(b) hereof, and use reasonable best efforts to cause
     such Registration Statement to become effective and remain effective as
     provided herein;

     (b) prepare and file with the SEC such amendments (including post-effective
     amendments) to such Registration Statement, and such supplements to the
     related Prospectus, as may be required by the applicable rules, regulations
     or instructions under the Securities Act during the applicable period, in
     accordance with the intended methods of disposition specified by the
     Holders of the Registrable Shares covered by such Registration Statement,
     make generally available earnings statements satisfying the provisions of
     Section 11(a) of the Securities Act (provided that the Corporation shall be
     deemed to have complied with this clause if it has complied with Rule 158
     under the Securities Act), and cause the related Prospectus as so
     supplemented to be filed pursuant to Rule 424 under the Securities Act, if
     necessary; PROVIDED, HOWEVER, that before filing a Registration Statement
     or Prospectus, or any amendments or supplements thereto (other than reports
     required to be filed by it under the Exchange Act), the Corporation shall
     furnish to the Holders of Registrable Shares covered by such Registration
     Statement and each counsel for such Holders and each managing underwriter,
     if any, for review and comment, copies of all documents required to be
     filed;


                                      -8-
<PAGE>


     (c) notify the Holders of any Registrable Shares covered by such
     Registration Statement promptly and (if requested) confirm such notice in
     writing, (i) when the Registration Statement, a Prospectus or Prospectus
     supplement or pre-effective or post-effective amendment thereto has been
     filed, and, with respect to such Registration Statement or any
     post-effective amendment, when the same has become effective, (ii) of the
     receipt by the Corporation of any notification with respect to any comments
     by the SEC with respect to such Registration Statement or Prospectus or any
     amendment or supplement thereto or of any request by the SEC for amendments
     or supplements to such Registration Statement or the related Prospectus or
     for additional information regarding such Holders, (iii) of the issuance by
     the SEC of any stop order suspending the effectiveness of such Registration
     Statement or the initiation of any proceedings for that purpose, (iv) of
     the receipt by the Corporation of any notification with respect to the
     suspension of the qualification or exemption from qualification of any of
     the Registrable Shares for sale in any jurisdiction or the initiation or
     threatening of any proceeding for such purpose and (v) of the happening of
     any event that requires the making of any changes in such Registration
     Statement, Prospectus or documents incorporated or deemed incorporated
     therein by reference so that they 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 not misleading;

     (d) use best efforts to obtain the withdrawal of any order suspending the
     effectiveness of such Registration Statement, or the lifting of any
     suspension of the qualification or exemption from qualification of any
     Registrable Shares for sale in any jurisdiction in the United States;

     (e) furnish to the Holder of any Registrable Shares covered by such
     Registration Statement, each counsel for such Holders and each managing
     underwriter, if any, without charge, one conformed copy of such
     Registration Statement, as declared effective by the SEC, and of each
     post-effective amendment thereto, in each case including financial
     statements and schedules and all exhibits and reports incorporated or
     deemed to be incorporated therein by reference; and deliver, without
     charge, such number of copies of the preliminary prospectus, any amended
     preliminary prospectus, each final Prospectus and any post-effective
     amendment or supplement thereto, as such Holder may reasonably request in
     order to facilitate the disposition of the Registrable Shares of such
     Holder covered by such Registration Statement in conformity with the
     requirements of the Securities Act;

     (f) prior to any public offering of Registrable Shares covered by such
     Registration Statement, use reasonable best efforts to register or qualify
     such Registrable Shares for offer and sale under the securities or "blue
     sky" laws of such jurisdictions as the Holders of such Registrable Shares
     shall reasonably request in writing and to keep such registrations or
     qualifications in effect for so long as the Registration Statement covering
     such Registrable Shares remains in effect; PROVIDED, HOWEVER, that the
     Corporation shall in no event be required to qualify generally to do
     business as a foreign corporation or as a dealer in any jurisdiction where
     it is not at the time so qualified or to take any action that would subject
     it to taxation in any such jurisdiction where it is not then subject;


                                      -9-
<PAGE>



     (g) upon the occurrence of any event contemplated by Section 5(c)(v) above,
     prepare a supplement or post-effective amendment to such Registration
     Statement or the related Prospectus or any document incorporated or deemed
     to be incorporated therein by reference and file any other required
     document so that, as thereafter delivered to the purchasers of the
     Registrable Shares being sold thereunder (including upon the termination of
     any Delay Period), such Prospectus will not contain an 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;

     (h) use its best efforts to cause all Registrable Shares covered by such
     Registration Statement to be listed on each securities exchange, if any, on
     which similar securities issued by the Corporation are then listed or if no
     such securities are so listed, to use its best efforts to cause all such
     Registrable Shares to be listed or quoted on a national securities
     exchange, the NASD Over The Counter Bulletin Board, or the Nasdaq Stock
     Market and, if quoted on the Nasdaq Stock Market, use its best efforts to
     secure designation of all such Registrable Shares as "NASDAQ Securities"
     within the meaning of Rules 11Aa2-1 and 11Aa3-1 promulgated under the
     Exchange Act or, failing that, to secure Nasdaq Stock Market authorization
     for such Registrable Shares and, without limiting the generality of the
     foregoing, to arrange for at least two market makers to register as such
     with respect to such Registrable Shares with the NASD;

     (i) on or before the effective date of such Registration Statement, provide
     the transfer agent of the Corporation for the Registrable Shares with
     printed certificates for the Registrable Shares covered by such
     Registration Statement, which are in a form eligible for deposit with The
     Depository Trust Company;

     (j) make available for inspection by any Holder of Registrable Shares
     included in such Registration Statement, any underwriter participating in
     any offering pursuant to such Registration Statement, and any attorney,
     accountant or other agent retained by any such Holder or underwriter
     (collectively, the "INSPECTORS"), all financial and other records and other
     information, pertinent corporate documents and properties of any of the
     Corporation, its subsidiaries and Affiliates (collectively, the "RECORDS"),
     as shall be reasonably necessary to enable them to exercise their due
     diligence responsibilities; PROVIDED, HOWEVER, that the Records that the
     Corporation determines, in good faith, to be confidential and which it
     notifies the Inspectors in writing are confidential shall not be disclosed
     by any Inspector unless (i) the disclosure of such Records is necessary to
     avoid or correct a misstatement in, or omission from, such Registration
     Statement or Prospectus, (ii) the release of such Records is ordered
     pursuant to a subpoena or other order from a court of competent
     jurisdiction or (iii) such Records have been made generally available to
     the public; PROVIDED FURTHER, HOWEVER, that (A) any decision regarding the
     disclosure of information pursuant to subclause (i) shall be made only
     after consultation with counsel for the applicable Inspectors and the
     Corporation and (B) with respect to any release of Records pursuant to
     subclause (ii), each holder of Registrable Shares agrees that it shall,
     promptly after learning that disclosure of such Records is sought in a
     court having jurisdiction, give notice to the Corporation so that the
     Corporation, at the Corporation's expense, may undertake appropriate action
     to prevent disclosure of such Records; and


                                      -10-
<PAGE>


     (k) if such offering is an underwritten offering, enter into such
     agreements (including an underwriting agreement in form, scope and
     substance as is customary in underwritten offerings) and take all such
     other appropriate and reasonable actions requested by the managing
     underwriters or the Holders of a majority of the Registrable Shares being
     sold in connection therewith in order to expedite or facilitate the
     disposition of such Registrable Shares, and in such connection, (i) cause
     its counsel to provide opinions and updates thereof (which counsel and
     opinions (in form, scope and substance) shall be reasonably satisfactory to
     the managing underwriters and counsel to the Holders of the Registrable
     Shares being sold), addressed to each selling Holder of Registrable Shares
     covered by such Registration Statement and each of the underwriters as to
     the matters customarily covered in opinions requested in underwritten
     offerings and such other matters as may be reasonably requested by such
     counsel and underwriters, (ii) cause its independent certified public
     accountants to provide "cold comfort" letters and updates thereof (and, if
     necessary, any other independent certified public accountants of any
     subsidiary of the Corporation or of any business acquired by the
     Corporation for which financial statements and financial data are, or are
     required to be, included in the Registration Statement), addressed to each
     selling Holder of Registrable Shares covered by the Registration Statement
     (unless such accountants shall be prohibited from so addressing such
     letters by applicable standards of the accounting profession) and each of
     the underwriters, such letters to be in customary form and covering matters
     of the type customarily covered in "cold comfort" letters in connection
     with underwritten offerings and (iii) if requested and if an underwriting
     agreement is entered into, provide indemnification provisions and
     procedures reasonably requested by such underwriters. The above shall be
     done at each closing under such underwriting or similar agreement, or as
     and to the extent required under such agreements. The Corporation may
     require each Holder of Registrable Shares covered by a Registration
     Statement to furnish such information in writing regarding such Holder and
     such Holder's intended method of disposition of such Registrable Shares as
     it may from time to time reasonably request in writing. If any such
     information is not furnished by a Holder of Registrable Shares within a
     reasonable period of time after receipt of such request, the Corporation
     may exclude such Holder's Registrable Shares from such Registration
     Statement. Each Holder of Registrable Shares covered by a Registration
     Statement agrees that, upon receipt of any notice from the Corporation of
     the happening of any event of the kind described in Section 5(c)(ii),
     5(c)(iii), 5(c)(iv) or 5(c)(v) hereof, that such Holder shall forthwith
     discontinue disposition of any Registrable Shares covered by such
     Registration Statement or the related Prospectus until receipt of the
     copies of the supplement or amendment to such Prospectus or any document
     incorporated or deemed to be incorporated therein by reference,
     contemplated by Section 5(g) hereof, or until such Holder is advised in
     writing by the Corporation that the use of the applicable Prospectus may be
     resumed (such period during which disposition is discontinued being an
     "INTERRUPTION PERIOD") and, if requested by the Corporation, the Holder
     shall deliver to the Corporation (at the expense of the Corporation) all
     copies then in its possession, other than permanent file copies then in
     such Holder's possession, of the Prospectus covering such Registrable
     Shares at the time of receipt of such request. Each Holder of Registrable
     Shares covered by a Registration Statement further agrees not to utilize
     any material other than the applicable current preliminary prospectus or
     Prospectus in connection with the offering and/or sale of such Registrable
     Shares.


                                      -11-
<PAGE>



SECTION 6. REGISTRATION EXPENSES. Whether or not any Registration Statement is
filed or becomes effective, but subject to Section 2(e) hereof, the Corporation
shall pay all costs, fees and expenses incident to the Corporation's performance
of or compliance with this Agreement, including (i) all registration and filing
fees, including NASD filing fees, (ii) all fees and expenses of compliance with
securities or "blue sky" laws, including reasonable fees and disbursements of
counsel in connection therewith, (iii) printing expenses (including expenses of
printing certificates for Registrable Shares and of printing prospectuses if the
printing of prospectuses is requested by the Holders of the Registrable Shares
being sold or the managing underwriters, if any), (iv) messenger, telephone and
delivery expenses, (v) fees and disbursements of counsel for the Corporation,
(vi) fees and disbursements of all independent certified public accountants of
the Corporation (including expenses of any "cold comfort" letters required in
connection with this Agreement) and all other persons retained by the
Corporation in connection with such Registration Statement, (vii) reasonable
fees and disbursements of one counsel, per Registration, selected by the Holders
of a majority of the Registrable Shares being registered, to represent all such
Holders; PROVIDED, HOWEVER, that, in the case of a Registration pursuant to
Section 3 hereof, the Corporation shall only be required to pay such fees and
disbursements of one counsel, per Registration, to represent all holders of
securities exercising "piggyback" registration rights in such Registration
(which counsel shall not represent the Corporation and shall be acceptable to
the Holders of a majority of the Registrable Shares being registered in their
sole discretion), (viii) fees and disbursements of underwriters customarily paid
by the issuers or sellers of securities and (ix) all other costs, fees and
expenses incident to the Corporation's performance or compliance with this
Agreement. Notwithstanding the foregoing, any discounts, commissions or brokers'
fees or fees of similar securities industry professionals and any transfer taxes
relating to the disposition of the Registrable Shares by a Holder, will be
payable by such Holder and the Corporation will have no obligation to pay any
such amounts.

SECTION 7. UNDERWRITING REQUIREMENTS. (a) Subject to Section 7(b) hereof, the
Holders shall have the right, by written notice, to require that any Demand
Registration provide for an underwritten offering.

     (b) In the case of any underwritten offering pursuant to a Demand
     Registration, the Holders of a majority of the Registrable Shares to be
     registered in connection therewith shall select the institution or
     institutions that shall manage or lead such offering, which institution or
     institutions shall be satisfactory to the Corporation, in its sole and
     absolute discretion. In the case of any underwritten offering pursuant to a
     Piggyback Registration in connection with a public offering of Shares for
     the account of the Corporation, the Corporation shall select the
     institution or institutions that shall manage or lead such offering. No
     Holder shall be entitled to participate in an underwritten offering unless
     and until such Holder has entered into an underwriting or other agreement
     with such institution or institutions for such offering in such form as the
     Corporation and such institution or institutions shall determine.

SECTION 8.  INDEMNIFICATION.

     (a) INDEMNIFICATION BY THE CORPORATION. The Corporation shall, without
     limitation as to time, indemnify and hold harmless, to the full extent
     permitted by law, each Holder of Registrable Shares whose Registrable
     Shares are covered by a Registration Statement or Prospectus, the
     shareholders, members, partners, officers, directors and agents and
     employees of each of them, any other Person acting on behalf of each such
     Holder, each Person who controls each such Holder (within the meaning of
     Section 15 of the Securities Act or Section 20 of the Exchange Act) and the
     shareholders, members, partners, officers, directors, agents and employees
     of each such controlling Person, to the fullest extent lawful, from and


                                      -12-
<PAGE>


     against any and all losses, claims, damages, liabilities, judgments, costs
     (including, without limitation, costs of investigation, preparation and
     reasonable attorneys' fees) and expenses (collectively, "LOSSES"), as
     incurred, arising out of or based upon any untrue or alleged untrue
     statement of a material fact contained in such Registration Statement or
     Prospectus or any amendment or supplement thereto, or any preliminary
     prospectus, or arising out of or based upon any omission or alleged
     omission of a material fact required to be stated therein or necessary to
     make the statements therein (in the case of a Prospectus, in the light of
     the circumstances under which they were made) not misleading, except
     insofar as the same are based upon information furnished in writing to the
     Corporation by or on behalf of any such Holder expressly for use therein.

     (b) INDEMNIFICATION BY HOLDERS. In connection with any Registration
     Statement in which a Holder is participating, such Holder shall, without
     limitation as to time, severally and not jointly indemnify and hold
     harmless, to the full extent permitted by law, the Corporation, its
     shareholders, directors, officers, agents and employees, any other Person
     acting on behalf of the Corporation, each Person who controls the
     Corporation (within the meaning of Section 15 of the Securities Act and
     Section 20 of the Exchange Act) and the shareholders, members, partners,
     directors, officers, agents or employees of such controlling Persons, from
     and against any and all Losses arising out of or based upon any untrue or
     alleged untrue statement of a material fact contained in such Registration
     Statement or the related Prospectus or any amendment or supplement thereto,
     or any preliminary prospectus, or arising out of or based upon any omission
     or alleged omission of a material fact required to be stated therein or
     necessary to make the statements therein (in the case of a Prospectus, in
     the light of the circumstances under which they were made) not misleading,
     to the extent, but only to the extent, that such untrue or alleged untrue
     statement or omission or alleged omission is based upon any information
     furnished in writing by or on behalf of such Holder to the Corporation
     expressly for use in such Registration Statement or Prospectus. Each
     Holder's indemnity obligations under this Section 8 shall be limited to the
     total sales proceeds (net of all underwriting discounts and commissions)
     actually received by such Holder in connection with the applicable
     offering.

     (c) CONDUCT OF INDEMNIFICATION PROCEEDINGS. If any Person shall be entitled
     to indemnity hereunder (an "INDEMNIFIED PARTY"), such indemnified party
     shall give prompt notice to the party from which such indemnity is sought
     (the "INDEMNIFYING PARTY") of any claim or of the commencement of any
     proceeding with respect to which such indemnified party seeks
     indemnification or contribution pursuant hereto; PROVIDED, HOWEVER, that
     the delay or failure to so notify the indemnifying party shall not relieve
     the indemnifying party from any obligation or liability except to the
     extent that the indemnifying party has been prejudiced by such delay or
     failure. The indemnifying party shall have the right, exercisable by giving
     written notice to an indemnified party promptly after the receipt of
     written notice from such indemnified party of such claim or proceeding, to
     assume, at the indemnifying party's expense, the defense of any such claim


                                      -13-
<PAGE>


     or proceeding, with counsel reasonably satisfactory to such indemnified
     party; PROVIDED, HOWEVER, that (i) an indemnified party shall have the
     right to employ separate counsel in any such claim or proceeding and to
     participate in the defense thereof, but the fees and expenses of such
     counsel shall be at the expense of such indemnified party unless: (1) the
     indemnifying party agrees to pay such fees and expenses; (2) the
     indemnifying party fails promptly to assume the defense of such claim or
     proceeding or fails to employ counsel reasonably satisfactory to such
     indemnified party; or (3) the named parties to any proceeding (including
     impleaded parties) include both such indemnified party and the indemnifying
     party, and such indemnified party shall have been advised by counsel that
     there may be one or more legal defenses available to it that are
     inconsistent with those available to the indemnifying party or that a
     conflict of interest is likely to exist among such indemnified party and
     any other indemnified parties (in which case the indemnifying party shall
     not have the right to assume the defense of such action on behalf of such
     indemnified party); and (ii) subject to clause (3) above, the indemnifying
     party shall not, in connection with any one such claim or proceeding or
     separate but substantially similar or related claims or proceedings in the
     same jurisdiction, arising out of the same general allegations or
     circumstances, be liable for the fees and expenses of more than one firm of
     attorneys (together with appropriate local counsel) at any time for all of
     the indemnified parties, or for fees and expenses that are not patently
     unreasonable. Whether or not such defense is assumed by the indemnifying
     party, such indemnified party shall not be subject to any liability for any
     settlement made without its consent. The indemnifying party shall not
     consent to entry of any judgment or enter into any settlement without the
     consent of the indemnified party unless (i) there is no finding or
     admission of any violation of any rights of any Person and no effect on any
     other claims that may be made against the indemnified party, (ii) the sole
     relief provided is monetary damages that are paid in full by the
     indemnifying party and (iii) such judgment or settlement includes as an
     unconditional term thereof the giving by the claimant or plaintiff to such
     indemnified party of a release, in form and substance reasonably
     satisfactory to the indemnified party, from all liability in respect of
     such claim or litigation for which such indemnified party would be entitled
     to indemnification hereunder.

     (d) CONTRIBUTION. If the indemnification provided for in this Section 8 is
     unavailable to an indemnified party in respect of any Losses (other than in
     accordance with its terms), then each applicable indemnifying party, in
     lieu of indemnifying such indemnified party, shall contribute to the amount
     paid or payable by such indemnified party as a result of such Losses, in
     such proportion as is appropriate to reflect the relative fault of the
     indemnifying party, on the one hand, and such indemnified party, on the
     other hand, in connection with the actions, statements or omissions that
     resulted in such Losses as well as any other relevant equitable
     considerations. The relative fault of such indemnifying party, on the one
     hand, and indemnified party, on the other hand, shall be determined by
     reference to, among other things, whether any action in question, including
     any untrue statement of a material fact or omission or alleged omission to
     state a material fact, has been taken by, or relates to information
     supplied by, such indemnifying party or indemnified party, and the parties'
     relative intent, knowledge, access to information and opportunity to
     correct or prevent any such action, statement or omission. The amount paid
     or payable by a party as a result of any Losses shall be deemed to include
     any legal or other fees or expenses incurred by such party in connection
     with any investigation or proceeding. The parties hereto agree that it
     would not be just and equitable if contribution pursuant to this Section
     8(d) were determined by PRO RATA allocation or by any other method of
     allocation that does not take account of the equitable considerations
     referred to above. Notwithstanding the provisions of this Section 8(d), an
     indemnifying party that is a Holder shall not be required to contribute any
     amount which is in excess of the amount by which the total proceeds (net of
     all underwriting discounts and commissions) received by such Holder from
     the sale of the Registrable Shares sold by such Holder in the applicable
     offering exceeds the amount of any damages that such indemnifying party has
     otherwise been required to pay by reason of such untrue or alleged untrue
     statement or omission or alleged omission. No person guilty of fraudulent
     misrepresentation (within the meaning of Section 11(f) of the Securities
     Act) shall be entitled to contribution from any Person who was not guilty
     of such fraudulent misrepresentation.



                                      -14-
<PAGE>


SECTION 9. ADDITIONAL REGISTRATION RIGHTS. The Corporation shall not, without
the consent of all of the Holders, grant to any Person any registration rights
which have priority over or are otherwise inconsistent with the registration
rights granted pursuant to this Agreement.

SECTION 10. TRANSFERABILITY OF REGISTRATION RIGHTS. The registration rights set
forth in this Agreement are transferable to any transferee or purchaser of
Registrable Shares, subject to compliance with any transfer restrictions
contained in any agreement with the Corporation. Each such transferee or
purchaser of Registrable Shares must consent in writing to be bound by the terms
and conditions of this Agreement in order to acquire the rights granted pursuant
to this Agreement. Notwithstanding anything contained herein to the contrary,
the registration rights set forth in this Agreement may be transferred to any
Affiliate of the Securityholder by the Securityholder providing written notice
of such transfer to the Corporation.

SECTION 11. MISCELLANEOUS. (a) RULES 144 AND 144A. The Corporation covenants
that it will timely file any reports required to be filed by it under the
Securities Act and the Exchange Act so as to enable Holders holding Registrable
Shares to sell such Registrable Shares (i) without registration under the
Securities Act within the limitation of the exemptions provided by (A) Rules 144
and 144A under the Securities Act, as each such Rule may be amended from time to
time or (B) any similar rule or rules hereafter adopted by the SEC, so long as
the exemptions provided for in such Rules would otherwise be available to such
Holders at such time and/or (ii) pursuant to a registration statement on Form
S-3 (or any successor form thereto). Upon the request of any such Holder, the
Corporation will forthwith deliver to such Holder a written statement as to
whether it has complied with the reporting requirements of Rules 144 and 144A or
whether it qualifies as a registrant whose securities may be resold pursuant to
Form S-3 (or any successor form thereto).

     (b) TERMINATION. This Agreement and the obligations of the Corporation and
     the Holders hereunder (other than Section 8 hereof and except with respect
     to rights previously exercised in connection with a public offering
     pursuant to Sections 2 or 3 hereof) shall terminate on the first date on
     which all of the Holders' shares of Common Stock can be sold, in the
     written opinion of counsel for the Corporation, pursuant to subsection (k)
     of Rule 144 under the Securities Act.

     (c) NOTICES. All notices, demands, requests or other communications that
     may be or are required to be given, served, or sent by any party to any
     other party pursuant to this Agreement shall be in writing and shall be
     mailed by first-class, registered or certified mail, return receipt
     requested, postage prepaid, or transmitted by hand delivery (including
     delivery by internationally recognized overnight courier), or facsimile
     transmission, addressed as follows:


                                      -15-
<PAGE>


                           (i) If to the Corporation:

                                    Allion Healthcare, Inc.
                                    33 Walt Whitman Road
                                    Suite 200A
                                    Huntington Station, NY 11046

                           with a copy to:

                                    Belin Lamson McCormick Zumbach Flynn
                                    A Professional Corporation
                                    The Financial Center
                                    666 Walnut, Suite 2000
                                    Des Moines, IA  50309
                                    Attention:  Garth D. Adams, Esq.
                                    Facsimile: (515) 558-0664

                           (ii) If to Securityholder:

                                    Gainesborough, L.L.C.
                                    420 Bedford Street, Suite 110
                                    Lexington, MA  02420

Each party may designate by notice in writing a new address to which any notice,
demand, request or communication may thereafter be so given, served or sent.
Each notice, demand, request or communication shall be deemed to have been duly
given at the earlier of its receipt or five Business Days after being deposited
in the mail, postage prepaid, if mailed; when delivered by hand, if personally
delivered; at the earlier of its receipt or three Business Days following
dispatch, if delivered by internationally recognized overnight courier; or upon
receipt, if sent by facsimile (followed by a confirmation copy sent by either
overnight or two-day courier).

     (d) SEVERABILITY. Whenever possible, each provision of this Agreement will
     be interpreted in such manner as to be effective and valid under applicable
     law, but if any provision of this Agreement is held to be invalid, illegal
     or unenforceable in any respect under any applicable law or rule in any
     jurisdiction, such invalidity, illegality or unenforceability will not
     affect any other provision or any other jurisdiction, and such invalid,
     void or otherwise unenforceable provisions shall be null and void. It is
     the intent of the parties, however, that any invalid, void or otherwise
     unenforceable provisions be automatically replaced by other provisions
     which are as similar as possible in terms to such invalid, void or
     otherwise unenforceable provisions but are valid and enforceable to the
     fullest extent permitted by law.

     (e) SUCCESSORS AND ASSIGNS. This Agreement shall be binding upon and inure
     to the benefit of the parties hereto and, subject to Section 10 hereof,
     their respective heirs, devisees, legatees, legal representatives,
     successors and assigns.

     (f) NO THIRD PARTY BENEFICIARY. The terms and provisions of this Agreement
     are intended solely for the benefit of each party hereto, their respective
     successors or assigns and any other holder of Registrable Shares, and it is
     not the intention of the parties to confer third-party beneficiary rights
     upon any other Person other than any Person entitled to indemnity under
     Section 8.


                                      -16-
<PAGE>


     (g) ENTIRE AGREEMENT. This Agreement represents the entire agreement of the
     parties and shall supersede any and all previous contracts, arrangements or
     understandings between the parties hereto with respect to the subject
     matter hereof.

     (h) AMENDMENTS AND WAIVERS. Except as otherwise provided herein, the
     provisions of this Agreement may not be amended, modified or supplemented,
     and waivers or consents to departures from the provisions hereof may not be
     given, unless the Corporation has obtained the written consent of the
     Holders of at least a majority in number of the Registrable Shares.

     (i) INTERPRETATION. The headings contained in this Agreement are for
     reference purposes only and shall not affect in any way the meaning or
     interpretation of this Agreement.

     (h) COUNTERPARTS. This Agreement may be executed in two or more
     counterparts, all of which shall be one and the same agreement, and shall
     become effective when counterparts have been signed by each of the parties
     and delivered to each other party.

     (i) REMEDIES.

         (a) No remedy conferred by any of the provisions of this Agreement is
         intended to be exclusive of any other remedy, and each and every remedy
         shall be cumulative and shall be in addition to every other remedy
         given hereunder or now or hereafter existing at law or in equity or by
         statute or otherwise. The election of any one or more remedies by any
         party hereto shall not constitute a waiver by any such party of the
         right to pursue any other available remedies.

         (b) It is acknowledged that a breach of the provisions of this
         Agreement could not be compensated adequately by money damages.
         Accordingly, any party hereto shall be entitled, in addition to any
         other right or remedy available to it, to an injunction restraining
         such breach or threatened breach and to specific performance of any
         provisions of this Agreement, and in either case no bond or other
         security shall be required in connection therewith. If any action shall
         be brought in equity to enforce any of the provisions of this
         Agreement, none of the parties hereto shall raise the defense that
         there is an adequate remedy at law and each of the parties hereto
         waives any and all defenses it may have on the ground of lack of
         jurisdiction or competence of the court to grant such injunction or
         other equitable relief. The existence of this right will not preclude
         any such Person from pursuing any other rights and remedies at law or
         in equity which such Person may have.

     (k) GOVERNING LAW; CONSENT TO JURISDICTION AND VENUE. IN ALL RESPECTS,
     INCLUDING ALL MATTERS OF CONSTRUCTION, VALIDITY AND PERFORMANCE, THIS
     AGREEMENT AND THE OBLIGATIONS ARISING HEREUNDER SHALL BE GOVERNED BY, AND
     CONSTRUED AND ENFORCED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW
     YORK APPLICABLE TO CONTRACTS MADE AND PERFORMED IN SUCH STATE, WITHOUT
     REGARD TO THE PRINCIPLES THEREOF REGARDING CONFLICTS OF LAWS, AND ANY
     APPLICABLE LAWS OF THE UNITED STATES OF AMERICA. The parties to this
     Agreement agree that jurisdiction and venue in any action brought by any


                                      -17-
<PAGE>


     party hereto pursuant to this Agreement shall properly (but not
     exclusively) lie in any New York State court located in the City of New
     York or any federal court of the United States sitting in the Southern
     District of New York, located in New York County. By execution and delivery
     of this Agreement, each of the parties hereto irrevocably submits to the
     jurisdiction of such courts for itself or himself and in respect of its or
     his property with respect to such action. THE PARTIES HERETO IRREVOCABLY
     AGREE THAT VENUE WOULD BE PROPER IN ANY SUCH COURT, AND HEREBY WAIVE ANY
     OBJECTION THAT ANY SUCH COURT IS AN IMPROPER OR INCONVENIENT FORUM FOR THE
     RESOLUTION OF SUCH ACTION. The parties further agree that the mailing by
     certified or registered mail, return receipt requested, of any process
     required by any such court shall constitute valid and lawful service of
     process against them, without necessity for service by any other means
     provided by statute or rule of court. Nothing herein shall preclude any
     party hereto from bringing suit or taking other legal action in any other
     jurisdiction.

     (l) CALCULATION OF TIME PERIODS. Except as otherwise indicated, all periods
     of time referred to herein shall include all Saturdays, Sundays and
     holidays; PROVIDED, HOWEVER, that if the date to perform the act or give
     any notice with respect to this Agreement shall fall on a day other than a
     Business Day, such act or notice may be timely performed or given if
     performed or given on the next succeeding Business Day.

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
















                                      -18-
<PAGE>


IN WITNESS WHEREOF, the parties hereto have executed this Registration Rights
Agreement as of the date and year first written above.

                                               ALLION HEALTHCARE, INC.

                                               By:  /s/ Michael P. Moran
                                               ------------------------------
                                               Name:  Michael P. Moran
                                               Title:  President and CEO

                                               SECURITYHOLDER:

                                               GAINESBOROUGH, L.L.C.

                                               By:  /s/ George D. Behrakis
                                               ------------------------------
                                               Name:  George D. Behrakis
                                               Title:  Chairman
























                                      -19-
<PAGE>