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                                                                     Exhibit 4.1
                   FIRST SUPPLEMENTAL INDENTURE AND GUARANTEE

         FIRST SUPPLEMENTAL INDENTURE AND GUARANTEE (this "Supplemental
Indenture"), dated as of February 27, 1998, among American Building Services,
Inc., UNICCO Service of N.J., Inc. (American Building Services, Inc. and UNICCO
Service of N.J., Inc. shall collectively be referred to herein as the
"Guaranteeing Restricted Subsidiaries"), each a Domestic Restricted Subsidiary
of UNICCO Service Company, a Massachusetts business trust (the "Company"),
UNICCO Finance Corp., a Delaware corporation ("Finance" and, together with the
Company, the "Issuers"), the other Guarantors (as defined in the Indenture
referred to herein) and State Street Bank and Trust Company, as trustee under
the indenture referred to below (the "Trustee").

                                   WITNESSETH

         WHEREAS, the Issuers have heretofore executed and delivered to the
Trustee an Indenture (the "Indenture"), dated as of October 17, 1997 providing
for the issuance of an aggregate principal amount of up to $150.0 million of 9
7/8% Senior Subordinated Notes due 2007 (the "Notes");

         WHEREAS, the Guaranteeing Restricted Subsidiaries have been acquired or
created by the Company as provided in Sections 4.18 and 11.04 of the Indenture;

         WHEREAS, the Indenture provides that under certain circumstances each
Guaranteeing Restricted Subsidiary shall execute and deliver to the Trustee a
supplemental indenture pursuant to which such Guaranteeing Restricted Subsidiary
shall unconditionally guarantee all of the Issuers' Obligations under the Notes
and the Indenture on the terms and conditions set forth herein (the "Note
Guarantee"); and

         WHEREAS, pursuant to Section 9.01 of the Indenture, the Trustee is
authorized to execute and deliver this Supplemental Indenture.

         NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the
Guaranteeing Restricted Subsidiaries and the Trustee mutually covenant and agree
for the equal and ratable benefit of the Holders of the Notes as follows:

         1. CAPITALIZED TERMS. Capitalized terms used herein without definition
shall have the meanings assigned to them in the Indenture.

         2. AGREEMENT TO GUARANTEE. The Guaranteeing Restricted Subsidiaries
hereby agree as follows:
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         (a)      Along with all the Guarantors named in the Indenture, to
                  jointly and severally Guarantee to each Holder of a Note
                  authenticated and delivered by the Trustee and to the Trustee
                  and its successors and assigns, irrespective of the validity
                  and enforceability of the Indenture, the Notes or the
                  obligations of the Issuers hereunder or thereunder, that:

                  (i)      the principal of and premium, interest and Liquidated
                           Damages, if any, on the Notes will be promptly paid
                           in full when due, whether at maturity, by
                           acceleration, redemption or otherwise, and interest
                           on the overdue principal of, premium, interest and
                           Liquidated Damages, if any, on the Notes, if any, if
                           lawful, and all other obligations of the Issuers to
                           the Holders or the Trustee hereunder or thereunder
                           will be promptly paid in full or performed, all in
                           accordance with the terms hereof and thereof; and

                  (ii)     in case of any extension of time of payment or
                           renewal of any Notes or any of such other
                           Obligations, the same will be promptly paid in full
                           when due or performed in accordance with the terms of
                           the extension or renewal, whether at stated maturity,
                           by acceleration or otherwise. Failing payment when
                           due of any amount so guaranteed or any performance so
                           guaranteed for whatever reason, the Guarantors shall
                           be jointly and severally obligated to pay the same
                           immediately.

         (b)      The obligations hereunder shall be unconditional, irrespective
                  of the validity, regularity or enforceability of the Notes or
                  the Indenture, the absence of any action to enforce the same,
                  any waiver or consent by any Holder of the Notes with respect
                  to any provisions hereof or thereof, the recovery of any
                  judgment against either of the Issuers, any action to enforce
                  the same or any other circumstance which might otherwise
                  constitute a legal or equitable discharge or defense of a
                  Guarantor.

         (c)      The following is hereby waived: diligence, presentment, demand
                  of payment, filing of claims with a court in the event of
                  insolvency or bankruptcy of either of the Issuers, any right
                  to require a proceeding first against the Issuers, protest,
                  notice and all demands whatsoever.

         (d)      This Note Guarantee shall not be discharged except by complete
                  performance of the Obligations contained in the Notes and the
                  Indenture.

         (e)      If any Holder or the Trustee is required by any court or
                  otherwise to return to the Issuers, the Guarantors, or any
                  custodian, trustee, liquidator or other similar official
                  acting in relation to either the Issuers or the Guarantors,
                  any amount paid by either to the Trustee or such Holder, this
                  Note 


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                  Guarantee, to the extent theretofore discharged, shall be
                  reinstated in full force and effect.

         (f)      The Guaranteeing Restricted Subsidiaries shall not be entitled
                  to any right of subrogation in relation to the Holders in
                  respect of any obligations guaranteed hereby until payment in
                  full of all Obligations guaranteed hereby.

         (g)      As between the Guarantors, on the one hand, and the Holders
                  and the Trustee, on the other hand, (x) the maturity of the
                  Obligations guaranteed hereby may be accelerated as provided
                  in Article 6 of the Indenture for the purposes of this Note
                  Guarantee, notwithstanding any stay, injunction or other
                  prohibition preventing such acceleration in respect of the
                  Obligations guaranteed hereby, and (y) in the event of any
                  declaration of acceleration of such Obligations as provided in
                  Article 6 of the Indenture, such Obligations (whether or not
                  due and payable) shall forthwith become due and payable by the
                  Guarantors for the purpose of this Note Guarantee.

         (h)      The Guarantors shall have the right to seek contribution from
                  any non-paying Guarantor so long as the exercise of such right
                  does not impair the rights of the Holders under the Note
                  Guarantee.

         (i)      Pursuant to Section 11.03 of the Indenture, after giving
                  effect to any maximum amount and any other contingent and
                  fixed liabilities that are relevant under any applicable
                  Bankruptcy or fraudulent conveyance laws, and after giving
                  effect to any collections from, rights to receive contribution
                  from or payments made by or on behalf of any other Guarantor
                  in respect of the Obligations of such other Guarantor under
                  Article 11 of the Indenture the Obligations of the Guarantors
                  shall be limited to the maximum amount as shall result in the
                  Obligations of such Guarantor under its Note Guarantee not
                  constituting a fraudulent transfer or conveyance.

         3. EXECUTION AND DELIVERY. Each Guaranteeing Restricted Subsidiary
agrees that the Note Guarantees shall remain in full force and effect
notwithstanding any failure to endorse on each Note a notation of such Note
Guarantee.

         4. GUARANTEEING RESTRICTED SUBSIDIARIES MAY CONSOLIDATE, ETC. ON
CERTAIN TERMS.

         (a)      The Guaranteeing Restricted Subsidiaries may not consolidate
                  with or merge with or into (whether or not such Guarantor is
                  the surviving Person) another corporation, Person or entity
                  whether or not affiliated with such Guarantor unless:


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                  (i)      subject to Section 11.05 of the Indenture, the Person
                           formed by or surviving any such consolidation or
                           merger (if other than a Guarantor or the Issuers)
                           unconditionally assumes all the obligations of such
                           Guarantor, pursuant to a supplemental indenture in
                           form and substance reasonably satisfactory to the
                           Trustee, under the Notes, the Indenture and the Note
                           Guarantee on the terms set forth herein or therein;
                           and

                  (ii)     immediately after giving effect to such transaction,
                           no Default or Event of Default exists.

         (b)      In case of any such consolidation, merger, sale or conveyance
                  and upon the assumption by the successor corporation, by
                  supplemental indenture, executed and delivered to the Trustee
                  and satisfactory in form to the Trustee, of the Note Guarantee
                  endorsed upon the Notes and the due and punctual performance
                  of all of the covenants and conditions of the Indenture to be
                  performed by the Guarantor, such successor corporation shall
                  succeed to and be substituted for the Guarantor with the same
                  effect as if it had been named herein as a Guarantor. Such
                  successor corporation thereupon may cause to be signed any or
                  all of the Note Guarantees to be endorsed upon all of the
                  Notes issuable hereunder which theretofore shall not have been
                  signed by the Issuers and delivered to the Trustee. All the
                  Note Guarantees so issued shall in all respects have the same
                  legal rank and benefit under the Indenture as the Note
                  Guarantees theretofore and thereafter issued in accordance
                  with the terms of the Indenture as though all of such Note
                  Guarantees had been issued at the date of the execution
                  hereof.

         (c)      Except as set forth in Articles 4 and 5 of the Indenture, and
                  notwithstanding clauses (a) and (b) above, nothing contained
                  in the Indenture or in any of the Notes shall prevent any
                  consolidation or merger of a Guarantor with or into the
                  Issuers or another Guarantor, or shall prevent any sale or
                  conveyance of the property of a Guarantor as an entirety or
                  substantially as an entirety to the Issuers or another
                  Guarantor.

         5.       RELEASES.

         (a)      In the event of a sale or other disposition of all of the
                  assets of any Guarantor, by way of merger, consolidation or
                  otherwise, or a sale or other disposition of all of the
                  capital stock of any Guarantor (other than to the Company or
                  another Guarantor), or in the case the Company designates a
                  Domestic Restricted Subsidiary to be an Unrestricted
                  Subsidiary in accordance with the Indenture, then such
                  Guarantor (in the event of a sale 


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                  or other disposition, by way of merger, consolidation or
                  otherwise, of all of the capital stock of such Guarantor) or
                  the corporation acquiring the property (in the event of a sale
                  or other disposition of all or substantially all of the assets
                  of such Guarantor) shall be released and relieved of any
                  obligations under its Note Guarantee; provided that the Net
                  Proceeds of such sale or other disposition are applied in
                  accordance with the applicable provisions of the Indenture,
                  including without limitation Section 4.10 of the Indenture.
                  Upon delivery by the Company to the Trustee of an Officers'
                  Certificate and an Opinion of Counsel to the effect that such
                  sale or other disposition was made by the Company in
                  accordance with the provisions of the Indenture, including
                  without limitation Section 4.10 of the Indenture, the Trustee
                  shall execute any documents reasonably required in order to
                  evidence the release of any Guarantor from its obligations
                  under its Note Guarantee.

         (b)      Any Guarantor not released from its obligations under its Note
                  Guarantee shall remain liable for the full amount of principal
                  of and interest on the Notes and for the other obligations of
                  any Guarantor under the Indenture as provided in Article 10 of
                  the Indenture.

         6. NO RECOURSE AGAINST OTHERS. No past, present or future director,
officer, employee, trustee, incorporator, shareholder or agent of the
Guaranteeing Restricted Subsidiaries, as such, shall have any liability for any
obligations of the Issuers or any Guaranteeing Restricted Subsidiary under the
Notes, any Note Guarantees, the Indenture or this Supplemental Indenture or for
any claim based on, in respect of, or by reason of, such obligations or their
creation. Each Holder of the Notes by accepting a Note waives and releases all
such liability. The waiver and release are part of the consideration for
issuance of the Notes. Such waiver may not be effective to waive liabilities
under the federal securities laws and it is the view of the Commission that such
a waiver is against public policy.

         7. NEW YORK LAW TO GOVERN. THE INTERNAL LAW OF THE STATE OF NEW YORK
SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENT INDENTURE BUT WITHOUT
GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT
THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

         8. COUNTERPARTS. The parties may sign any number of copies of this
Supplemental Indenture. Each signed copy shall be an original, but all of them
together represent the same agreement.

         9. EFFECT OF HEADINGS. The Section headings herein are for convenience
only and shall not affect the construction hereof.


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         10. THE TRUSTEE. The Trustee shall not be responsible in any manner
whatsoever for or in respect of the validity or sufficiency of this Supplemental
Indenture or for or in respect of the recitals contained herein, all of which
recitals are made solely by the Guaranteeing Restricted Subsidiaries and the
Issuers.


                                       SIGNATURES

         Dated as of the date first set forth above.


                                         AMERICAN BUILDING SERVICES, INC.

                                         By:  /s/ George A. Keches
                                             --------------------------
                                             Name: George A. Keches
                                             Title: Treasurer



                                         UNICCO SERVICE OF N.J., INC.

                                         By:  /s/ George A. Keches
                                             --------------------------
                                             Name: George A. Keches
                                             Title: Treasurer



                                         UNICCO SERVICE COMPANY

                                         By:  /s/ George A. Keches
                                             --------------------------
                                             Name: George A. Keches
                                             Title: Vice President - Finance and
                                                    Administration



                                         UNICCO FINANCE CORP.

                                         By:  /s/ George A. Keches
                                             --------------------------
                                             Name: George A. Keches
                                             Title: Treasurer


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                                         USC, INC.

                                         By: /s/ George A. Keches
                                             --------------------------
                                             Name: George A. Keches
                                             Title: Treasurer



                                         UNICCO GOVERNMENT SERVICES,
                                         INC.

                                         By: /s/ George A. Keches
                                             --------------------------
                                             Name: George A. Keches
                                             Title: Treasurer



                                         UNICCO SECURITY SERVICES, INC.

                                         By: /s/ George A. Keches
                                             --------------------------
                                             Name: George A. Keches
                                             Title: Assistant Treasurer



    STATE STREET BANK AND TRUST
    COMPANY, AS TRUSTEE

    By: /s/ Andrew M. Sinasky
        -------------------------------
        Name: Andrew M. Sinasky
        Title: Assistant Vice President



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