EXHIBIT 99.3
 
                             LETTER OF TRANSMITTAL
 
                                   TO TENDER
              UNREGISTERED 13% SENIOR DISCOUNT DEBENTURES DUE 2009
 
                                       OF
 
                               MEDIQ INCORPORATED
 
    PURSUANT TO THE EXCHANGE OFFER AND PROSPECTUS DATED               , 1998
 
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    THE EXCHANGE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 5:00 P.M., NEW YORK
   CITY TIME, ON               , 1998 (THE "EXPIRATION DATE"), UNLESS THE
   EXCHANGE OFFER IS EXTENDED BY THE COMPANY.
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                 THE EXCHANGE AGENT FOR THE EXCHANGE OFFER IS:
 
                          UNITED STATES TRUST COMPANY
                                  OF NEW YORK
 

                                                      
  BY OVERNIGHT COURIER AND       BY HAND UP TO 4:30 PM:      BY REGISTERED OR CERTIFIED MAIL:
  BY HAND AFTER 4:30 PM ON
 THE EXPIRATION DATE ONLY:
United States Trust Company   United States Trust Company      United States Trust Company
        of New York                   of New York                      of New York
  770 Broadway, 13th Floor            111 Broadway                     P.O. Box 844
  New York, New York 10003            Lower Level                     Cooper Station
   Attn: Corporate Trust        New York, New York 10006      New York, New York 10276-0844
          Services               Attn: Corporate Trust        Attn: Corporate Trust Services
                                        Services
                               Telephone: (800) 548-6565
                               Facsimile: (212) 780-0592
                                     (212) 420-6211

 
    (Originals of all documents sent by facsimile should be sent promptly by
                                   registered
       or certified mail, hand delivery, or overnight delivery service.)
 
  DELIVERY OF THIS LETTER OF TRANSMITTAL TO AN ADDRESS OR TRANSMISSION OF
      INSTRUCTIONS VIA FACSIMILE OTHER THAN AS SET FORTH ABOVE WILL NOT
                          CONSTITUTE A VALID DELIVERY.
 
IF YOU WISH TO EXCHANGE UNREGISTERED 13% SENIOR DISCOUNT DEBENTURES DUE 2009
  FOR AN EQUAL AGGREGATE PRINCIPAL AMOUNT AT MATURITY OF REGISTERED 13%
    SENIOR DISCOUNT DEBENTURES DUE 2009 PURSUANT TO THE EXCHANGE OFFER,
      YOU MUST VALIDLY TENDER (AND NOT WITHDRAW) SUCH UNREGISTERED NOTES
              TO THE EXCHANGE AGENT PRIOR TO THE EXPIRATION DATE.
 
                          SIGNATURES MUST BE PROVIDED
 
              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY.

 


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                             DESCRIPTION OF TENDERED DEBENTURES
- -------------------------------------------------------------------------------------------
                                                            CERTIFICATE    PRINCIPAL AMOUNT
     NAMES(S) AND ADDRESS(ES) OF REGISTERED OWNER(S)         NUMBER(S)      AT MATURITY OF
 AS THEY APPEAR ON THE UNREGISTERED 13% SENIOR DISCOUNT    OF DEBENTURES      DEBENTURES
     DEBENTURES DUE 2009 (PLEASE FILL IN, IF BLANK)           TENDERED         TENDERED
                                                                     
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                                                           ---------------------------------
 
                                                           ---------------------------------
 
                                                           ---------------------------------
 
                                                           ---------------------------------
 
                                                           ---------------------------------
 
                                                           ---------------------------------
 
                                                           ---------------------------------
                                                               TOTAL
                                                             PRINCIPAL
                                                             AMOUNT AT
                                                            MATURITY OF
                                                             DEBENTURES
                                                              TENDERED
 
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Ladies and Gentlemen:
 
    1. The undersigned hereby tenders to MEDIQ Incorporated, a Delaware
corporation (the "Company"), the 13% Senior Discount Debentures due 2009 (the
"Old Debentures") described above pursuant to the Company's offer of $1,000
principal amount at maturity of 13% Senior Discount Debentures due 2009 (the
"New Debentures"), in exchange for each $1,000 principal amount at maturity of
the Old Debentures, upon the terms and subject to the conditions contained in
the Prospectus dated            , 1998 (the "Prospectus"), receipt of which is
hereby acknowledged, and in this Letter of Transmittal (which together
constitute the "Exchange Offer").
 
    2. The undersigned hereby represents and warrants that it has full authority
to tender the Old Debentures described above. The undersigned will, upon
request, execute and deliver any additional documents deemed by the Company to
be necessary or appropriate to complete the tender of Old Debentures.
 
    3. The undersigned understands that the tender of the Old Debentures
pursuant to all of the procedures set forth in the Prospectus will constitute an
agreement between the undersigned and the Company as to the terms and conditions
set forth in the Prospectus.
 
    4. Unless the box under the heading "Special Registration Instructions" is
checked, the undersigned hereby represents and warrants that:
 
        (i) the New Debentures acquired pursuant to the Exchange Offer are being
    obtained in the ordinary course of business of the undersigned, whether or
    not the undersigned is the holder of the Old Debentures;
 
        (ii) neither the undersigned nor any such other person has an
    arrangement or understanding with any person to participate in the
    distribution of such New Debentures or Old Debentures within the meaning of
    the Securities Act of 1933, as amended (the "Securities Act");
 
        (iii) neither the undersigned nor any such other person is an
    "affiliate," as such term is defined under Rule 405 promulgated under the
    Securities Act, of the Company, or if it is an affiliate, the undersigned or
    such other person will comply with the registration and prospectus delivery
    requirements of the Securities Act to the extent applicable;
 
        (iv) if the undersigned or such other person is not a broker-dealer,
    neither the undersigned nor any such other person is engaged in or intends
    to engage in the distribution of such New Debentures; and
 
        (v) if the undersigned or such other person is a broker-dealer, the
    undersigned or such other person will receive New Debentures for its own
    account in exchange for Old Debentures that were acquired as the result of
    market making activities or other trading activities.
 
    5. The undersigned may, IF, AND ONLY IF, UNABLE TO MAKE ALL OF THE
REPRESENTATIONS AND WARRANTIES CONTAINED IN ITEM 4 ABOVE, elect to have its Old
Debentures registered in the shelf registration described in the Registration
Rights Agreement, dated May 21, 1998, among the Company, MEDIQ/PRN Life Support
Services, Inc., a Delaware corporation and a wholly-owned subsidiary of the
Company ("MEDIQ/PRN"), certain guarantors of obligations under the 11% Senior
Subordinated Notes due 2008 of MEDIQ/PRN (the "Guarantors") and the initial
purchasers of the Old Debentures (the "Registration Rights Agreement;" all
capitalized terms used in this Item 5, unless otherwise defined herein, shall
have the meanings given them in the Registration Rights Agreement), a conformed
copy of which has been filed as an exhibit to the Registration Statement of
which the Prospectus constitutes a part. Such election may be made by checking
the box under "Special Registration Instructions." By making such election, the
undersigned agrees, as a holder of Transfer Restricted Securities participating
in a shelf registration, to indemnify and hold harmless the Company, its
directors and officers and each person, if any, who controls the Company within
the meaning of either Section 15 of the Securities Act or Section 20 of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), from and
against any losses, claims, damages or liabilities, joint or several, or any
actions in respect thereof (including, but not limited to, any losses, claims,
damages, liabilities or actions relating to purchases and

sales of the New Debentures) to which the Company, MEDIQ/PRN, any Guarantor or
any such director, officer or controlling person may become subject under the
Securities Act, the Exchange Act or otherwise, insofar as such losses, claims,
damages, liabilities or actions arise out of, or are based upon, any untrue
statement or alleged untrue statement of a material fact contained in a
registration statement or prospectus or in any amendment or supplement thereto
or in any preliminary prospectus relating to a shelf registration, or arise out
of, or are based upon, the omission or alleged omission to state therein a
material fact or necessary to make the statement therein not misleading, but in
each case only to the extent that the untrue statement or omission or alleged
untrue statement or omission was made in reliance upon and in conformity with
written information pertaining to the undersigned and furnished to the Company
by or on behalf of the undersigned specifically for inclusion therein. Any such
indemnification shall be governed by the terms and subject to the conditions set
forth in the Registration Rights Agreement, including, without limitation, the
provisions regarding notice, retention of counsel, contribution and payment of
expenses set forth therein. The above summary of the indemnification provisions
of the Registration Rights Agreement is not intended to be exhaustive and is
qualified in its entirety by reference to the Registration Rights Agreement.
 
    6. If the undersigned is a broker-dealer that will receive New Debentures
for its own account in exchange for Old Debentures that were acquired as a
result of market-making activities or other trading activities, it acknowledges
that it will deliver a prospectus in connection with any resale of such New
Debentures; however, by so acknowledging and delivering a prospectus, the
undersigned will not be deemed to admit that it is an "underwriter" within the
meaning of the Securities Act. If the undersigned is a broker-dealer and Old
Debentures held for its own account were not acquired as a result of market-
making or other trading activities, such Old Debentures cannot be exchanged
pursuant to the Exchange Offer.
 
    7. Any obligation of the undersigned hereunder shall be binding upon the
successors, assigns, executors, administrators, trustees in bankruptcy and legal
and personal representatives of the undersigned.
 
    8. Unless otherwise indicated herein under "Special Delivery Instructions,"
the certificates for the New Debentures will be issued in the name of the
undersigned.

                         SPECIAL DELIVERY INSTRUCTIONS
                              (SEE INSTRUCTION 1)
 
    To be completed ONLY IF the New Debentures are to be issued or sent to
someone other than the undersigned or to the undersigned at an address other
than that provided above.
 
        Mail / /  Issue / /  (Check appropriate boxes) certificates to:
 
Name: __________________________________________________________________________
                                 (Please Print)
 
Address: _______________________________________________________________________
 
                                         _______________________________________
 
                                         _______________________________________
 
                              (Including Zip Code)
 
                       SPECIAL REGISTRATION INSTRUCTIONS
 
                                  (SEE ITEM 5)
 
    To be completed ONLY IF (i) the undersigned satisfies the conditions set
forth in Item 5 above, (ii) the undersigned elects to register its Old
Debentures in the shelf registration described in the Registration Rights
Agreement, and (iii) the undersigned agrees to indemnify certain entities and
individuals as set forth in the Registration Rights Agreement and summarized in
Item 5 above.
 
    / /  By checking this box the undersigned hereby (i) represents that it is
unable to make all of the representations and warranties set forth in Item 4
above, (ii) elects to have its Old Debentures registered pursuant to the shelf
registration described in the Registration Rights Agreement, and (iii) agrees to
indemnify certain entities and individuals identified in, and to the extent
provided in, the Registration Rights Agreement and summarized in Item 5 above.
 
                       SPECIAL BROKER-DEALER INSTRUCTIONS
                                  (SEE ITEM 6)
 
    / /  Check here if you are a broker-dealer and wish to receive 10 additional
copies of the Prospectus and 10 copies of any amendments or supplements thereto.
 
Name: __________________________________________________________________________
                                 (Please Print)
 
Address: _______________________________________________________________________
 
                                         _______________________________________
 
                                         _______________________________________
 
                              (Including Zip Code)

                                   SIGNATURE
 
    To be completed by all exchanging debentureholders. Must be signed by the
registered holder exactly as such holder's name appears on the Old Debentures.
If the signature is by a trustee, executor, administrator, guardian,
attorney-in-fact, officer of a corporation or other person acting in a fiduciary
or representative capacity, please set forth such person's full title. See
Instruction 3.
 
X ______________________________________________________________________________
 
X ______________________________________________________________________________
          Signature(s) of Registered Holder(s) or Authorized Signature
 
Dated: _________________________________________________________________________
 
Name(s): _______________________________________________________________________
 
________________________________________________________________________________
                             (Please Type or Print)
 
Capacity: ______________________________________________________________________
 
Address: _______________________________________________________________________
 
                                         _______________________________________
 
                                         _______________________________________
                              (Including Zip Code)
 
Area Code and Telephone No.: ___________________________________________________
 
               SIGNATURE GUARANTEE (IF REQUIRED BY INSTRUCTION 1)
 
        CERTAIN SIGNATURES MUST BE GUARANTEED BY AN ELIGIBLE INSTITUTION
 
________________________________________________________________________________
             (Name of Eligible Institution Guaranteeing Signatures)
 
________________________________________________________________________________
  (Address (including zip code) and Telephone Number (including area code) of
                                     Firm)
 
________________________________________________________________________________
                             (Authorized Signature)
 
________________________________________________________________________________
                                 (Printed Name)
 
________________________________________________________________________________
                                    (Title)
 
Dated: _________________________________________________________________________

                      PLEASE READ THE INSTRUCTIONS BELOW,
                WHICH FORM A PART OF THIS LETTER OF TRANSMITTAL.
 
                                  INSTRUCTIONS
 
    1. GUARANTEE OF SIGNATURES. Signatures on this Letter of Transmittal must be
guaranteed by an eligible guarantor institution that is a member of or
participant in the Securities Transfer Agents Medallion Program, the New York
Stock Exchange Medallion Signature Program, the Stock Exchange Medallion
Program, or by an "eligible guarantor institution" within the meaning of Rule
17Ad-15 promulgated under the Exchange Act (an "Eligible Institution") unless
the box entitled "Special Registration Instructions" or "Special Delivery
Instructions" above has not been completed or the Old Debentures described above
are tendered for the account of an Eligible Institution.
 
    2. DELIVERY OF LETTER OF TRANSMITTAL AND OLD DEBENTURES. The Old Debentures,
together with a properly completed and duly executed Letter of Transmittal (or
copy thereof), should be mailed or delivered to the Exchange Agent at the
address set forth above.
 
    THE METHOD OF DELIVERY OF OLD DEBENTURES AND THE LETTER OF TRANSMITTAL AND
ALL OTHER REQUIRED DOCUMENTS TO THE EXCHANGE AGENT IS AT THE ELECTION AND RISK
OF THE HOLDER. INSTEAD OF DELIVERY BY MAIL, IT IS RECOMMENDED THAT HOLDERS USE
AN OVERNIGHT OR HAND DELIVERY SERVICE. IN ALL CASES, SUFFICIENT TIME SHOULD BE
ALLOWED TO ENSURE DELIVERY TO THE EXCHANGE AGENT BEFORE THE EXPIRATION DATE. NO
LETTER OF TRANSMITTAL OR OLD DEBENTURES SHOULD BE SENT TO THE COMPANY. HOLDERS
MAY REQUEST THEIR RESPECTIVE BROKERS, DEALERS, COMMERCIAL BANKS, TRUST
COMPANIES, OR NOMINEES TO EFFECT THE ABOVE TRANSACTIONS FOR SUCH HOLDERS.
 
    3. SIGNATURE ON LETTER OF TRANSMITTAL, BOND POWERS AND ENDORSEMENTS. If this
Letter of Transmittal is signed by a person other than a registered holder of
any Old Debentures, such Old Debentures must be endorsed or accompanied by
appropriate bond powers, signed by such registered holder exactly as such
registered holder's name appears on such Old Debentures.
 
    If this Letter of Transmittal or any Old Debentures or bond powers are
signed by trustees, executors, administrators, guardians, attorneys-in-fact,
officers of corporations, or others acting in a fiduciary or representative
capacity, such persons should so indicate when signing, and, unless waived by
the Company, proper evidence satisfactory to the Company of their authority to
so act must be submitted with this Letter of Transmittal.
 
    4. MISCELLANEOUS. All questions as to the validity, form, eligibility
(including time of receipt), acceptance, and withdrawal of tendered Old
Debentures will be determined by the Company in its sole discretion, which
determination will be final and binding on all parties. The Company reserves the
absolute right to reject any or all Old Debentures not properly tendered or any
Old Debentures the Company's acceptance of which would, in the opinion of
counsel for the company, be unlawful. The Company also reserves the right to
waive any defects, irregularities, or conditions of tender as to particular Old
Debentures. The Company's interpretation of the terms and conditions of the
Exchange Offer (including the instructions in this Letter of Transmittal) will
be final and binding. Unless waived, any defects or irregularities in connection
with tenders of Old Debentures must be cured within such time as the Company
shall determine. Neither the Company, the Exchange Agent, nor any other person
shall be under any duty to give notification of defects in such tenders or shall
incur any liability for failure to give such notification. Tenders of Old
Debentures will not be deemed to have been made until such defects or
irregularities have been cured or waived. Any Old Debentures received by the
Exchange Agent that are not properly tendered and as to which the defects or
irregularities have not been cured or waived will be returned by the Exchange
Agent to the tendering holder thereof as soon as practicable following the
Expiration Date.