POWER OF ATTORNEY

           Know all by these present, that the undersigned hereby constitutes
and appoints each of Michael P. Moran and James G. Spencer, signing singly, the
undersigned's true and lawful attorney-in-fact to:

           (1) execute for and on behalf of the undersigned, in the
           undersigned's capacity as an officer and/or director of Allion
           Healthcare, Inc. (the "Company"), Forms 3, 4, and 5, Form ID or such
           other forms as the United States Securities and Exchange Commission
           may from time to time adopt for reporting changes in beneficial
           ownership of the Company's securities, in accordance with Section
           16(a) of the Securities Exchange Act of 1934 and the rules
           promulgated thereunder.

           (2) do and perform any and all acts for and on behalf of the
           undersigned which may be necessary or desirable to complete and
           execute any such Form, complete and execute any amendment or
           amendments thereto, and file such Form with the United States
           Securities and Exchange Commission and any stock exchange or similar
           authority; and

           (3) take any other action of any type whatsoever in connection with
           the foregoing which, in the opinion of such attorney-in-fact, may be
           of benefit to, in the best interest of, or legally required by, the
           undersigned, it being understood that the documents executed by such
           attorney-in-fact on behalf of the undersigned pursuant to this Power
           of Attorney shall be in such form and shall contain such terms and
           conditions as such attorney-in-fact may approve in such
           attorney-in-fact's discretion.

           The undersigned hereby grants to each such attorney-in-fact full
power and authority to do and perform any and every act and thing whatsoever
requisite, necessary, or proper to be done in the exercise of any of the rights
and powers herein granted, as fully to all intents and purposes as the
undersigned might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that such
attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall
lawfully do or cause to be done by virtue of this power of attorney and the
rights and powers herein granted. The undersigned acknowledges that the
foregoing attorneys-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming, nor is the Company assuming, any of the
undersigned's responsibilities to comply with Section 16 of the Securities
Exchange Act of 1934.

           This Power of Attorney shall remain in full force and effect until
revoked by the undersigned in a signed writing delivered in the foregoing
attorneys-in-fact.

           IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney
to be executed as of the 13th day of May, 2004.





                                                      /s/ JOHN PAPPAJOHN
                                                      ------------------
                                                       John Pappajohn