<PAGE>
Exhibit 10.12

                                                                  EXECUTION COPY

                           THIRD AMENDMENT TO AMENDED
                          AND RESTATED CREDIT AGREEMENT

     THIS THIRD  AMENDMENT  TO  AMENDED  AND  RESTATED  CREDIT  AGREEMENT  (this
"Agreement") dated as of the 19th day of December,  2001 (the  "Agreement"),  by
and among iPCS WIRELESS,  INC. (the "Borrower"),  a Delaware corporation,  iPCS,
INC.,   ("Holdings"),    a   Delaware   corporation,    iPCS   EQUIPMENT,   INC.
("Equipmentco"),  a Delaware  corporation  (collectively  with the  Borrower and
Holdings,  the "Loan Parties"),  the Lenders (as defined in the Credit Agreement
defined below), and TORONTO DOMINION (TEXAS), INC., as administrative agent (the
"Administrative Agent").

                              W I T N E S S E T H:
                               - - - - - - - - - -

     WHEREAS,  the Loan Parties,  the Lenders and the  Administrative  Agent are
parties to that certain Amended and Restated  Credit  Agreement dated as of July
12,  2000,  as amended by that certain  First  Amendment to Amended and Restated
Credit  Agreement  and Consent  dated as of February  23,  2001,  and as further
amended  by that  certain  Second  Amendment  to  Amended  and  Restated  Credit
Agreement and Consent dated as of September 28, 2001 (the "Credit Agreement");

     WHEREAS,  the Borrower has requested that the Lenders, and the Lenders have
agreed to, subject to the terms hereof, amend the Credit Agreement as more fully
set forth herein; and

     NOW,  THEREFORE,  in  consideration  of the premises  set forth above,  the
covenants  and  agreements  hereinafter  set forth,  and other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties  hereto  agree that all  capitalized  terms used and not defined  herein
shall have the meanings  ascribed thereto in the Credit  Agreement,  and further
agree as follows:

     1.   Amendment  to  Section  1.3.   Section  1.3,   Accounting   Terms  and
Determinations,   of  the  Credit  Agreement,  is  hereby  amended  by  deleting
subsection  (c)  in its  entirety  and  by  substituting  in  lieu  thereof  the
following:

          "(c) To enable the ready and  consistent  determination  of compliance
     with the  covenants set forth in this  Agreement,  neither the Borrower nor
     Holdings  will change the last day of its fiscal year from  September 30 or
     the last days of its first  three  fiscal  quarters  in each of its  fiscal
     years from December 31, March 31 and June 30, respectively."

     2. No Other  Amendment  or Waiver.  Notwithstanding  the  agreement  of the
Lenders  to the  terms  and  provisions  of this  Agreement,  the  Loan  Parties
acknowledge  and  expressly  agree that this  Agreement is limited to the extent
expressly set forth herein and shall not constitute a modification of the Credit
Agreement or any other Loan  Documents  or a course of dealing at variance  with
the terms of the Credit  Agreement  or any other Loan  Documents  (other than as
expressly set forth above) so as to require further notice by the Administrative
Agent or the Lenders,  or any of them, of its or their intent to require  strict
adherence to the terms of the Credit  Agreement and the other Loan  Documents in
the future. All of the terms, conditions, provisions and covenants of the Credit
Agreement and the other Loan Documents shall remain  unaltered and in full force
and effect except as expressly modified by this Agreement.  The Credit Agreement
and each other  Loan  Document  shall be deemed  modified  hereby  solely to the
extent necessary to effect the waivers and amendments contemplated hereby.

3. Representations and Warranties. The Loan Parties hereby represent and warrant
in favor of the Administrative Agent and each Lender as follows:

          (a) Each of the Loan Parties has the corporate power and authority (i)
     to enter  into this  Agreement  and (ii) to do all other acts and things as
     are required or contemplated  hereunder to be done,  observed and performed
     by them;

          (b) This Agreement has been duly and validly executed and delivered by
     each of the  Loan  Parties  that is a party  thereto,  and  such  Agreement
     constitutes  the legal,  valid and  binding  obligations  of such  Persons,
     enforceable  against each such Person in accordance  with their  respective
     terms, except as limited by bankruptcy, insolvency or other laws of general
     application  relating to the  enforcement of creditors'  rights and general
     principles of equity.

          (c) The execution and delivery of this  Agreement and the  performance
     by the Loan Parties under the Credit Agreement and the other Loan Documents
     to which each is a party,  as amended  hereby,  do not and will not require
     the  consent  or  approval  of any  regulatory  authority  or  governmental
     authority  or agency  having  jurisdiction  over the Loan Parties or any of
     their  Subsidiaries  which  has  not  already  been  obtained,  nor  is  in
     contravention of or in conflict with the articles of incorporation, by-laws
     or partnership agreements of the Loan Parties or any of their Subsidiaries,
     or any provision of any statute,  judgment,  order, or material  indenture,
     instrument, agreement, or undertaking to which Loan Parties or any of their
     Subsidiaries  is a party or by  which  any of their  respective  assets  or
     properties is or may become bound; and

          (d) The representations  and warranties  contained in Article 7 of the
     Credit  Agreement and contained in the other Loan Documents remain true and
     correct as of the date hereof,  both before and after giving effect to this
     Agreement, except to the extent previously fulfilled in accordance with the
     terms of the Credit  Agreement or such other Loan Document,  as applicable,
     or to the extent relating  specifically to the earlier date. No Default now
     exists or will be caused hereby.

     4. Conditions Precedent:  Effective Date. This Agreement shall be effective
as of the  Agreement  Date  subject  to  satisfaction  of each of the  following
conditions precedent:

          (a) all of the  representations  and  warranties of the Borrower under
     Section  3 hereof  which  are made as of the date  hereof,  being  true and
     correct in all material respects; and

          (b)  receipt  by  the  Administrative  Agent  of  counterparts  hereof
     executed by the Required Lenders and each of the Loan Parties.

5.       Guarantor Acknowledgment.

          (a) Each of Holdings and Equipmentco  has guarantied the  Obligations.
     Holdings  and  Equipmentco  are  collectively  referred  to  herein  as the
     "Guarantors",  and the Guaranty executed by each Guarantor are collectively
     referred to herein as the "Guaranties".

          (b) Each Guarantor hereby  acknowledges that it has reviewed the terms
     and provisions of the Credit  Agreement and this Agreement.  Each Guarantor
     hereby confirms that the Guaranty to which it is a party or otherwise bound
     will  continue  to  guarantee,  as the case may be, to the  fullest  extent
     possible in accordance  with such Guaranty the payment and  performance  of
     all "Obligations" under each of the Guaranties, as the case may be (in each
     case as such  terms are  defined  in the  applicable  Guaranty),  including
     without  limitation the payment and  performance of all such  "Obligations"
     under  each of the  Guaranties,  as the  case  may be,  in  respect  of the
     Obligations  of the Borrower now or hereafter  existing under or in respect
     of the Credit Agreement and the Notes defined therein.

          (c) Each Guarantor  acknowledges and agrees that any of the Guaranties
     to which it is a party or otherwise  bound shall continue in full force and
     effect  and  that all of its  obligations  thereunder  shall  be valid  and
     enforceable  and shall not be  impaired  or  limited  by the  execution  or
     effectiveness  of this  Agreement.  Each Guarantor  represents and warrants
     that all representations and warranties  contained in the Credit Agreement,
     this  Agreement and the Guaranty to which it is a party or otherwise  bound
     are true,  correct and complete in all  material  respects on and as of the
     date  hereof  to the same  extent as  though  made on and as of that  date,
     except to the  extent  such  representations  and  warranties  specifically
     relate to an  earlier  date,  in which  case they were  true,  correct  and
     complete in all material respects on and as of such earlier date.

          (d) Each Guarantor  acknowledges  and agrees that (i)  notwithstanding
     the conditions to effectiveness set forth in this Agreement, such Guarantor
     is not  required  by the terms of the  Credit  Agreement  or any other Loan
     Document  to consent to the  amendments  of the Credit  Agreement  effected
     pursuant to this Agreement and (ii) nothing in the Credit  Agreement,  this
     Agreement or any other Loan Document shall be deemed to require the consent
     of such Guarantor to any future amendments to the Credit Agreement.

     6.   Counterparts.   This  Agreement   maybe  executed  in  any  number  of
counterparts,  each of which  shall be  deemed to be an  original,  but all such
separate counterparts shall together constitute one and the same instrument.

     7. Loan Documents. Each reference in the Credit Agreement or any other Loan
Document to the term "Credit  Agreement"  shall  hereafter mean and refer to the
Credit Agreement as amended hereby and as the same may hereafter be amended.

     8. Governing Law. This Agreement  shall be construed in accordance with and
governed by the internal laws of the State of New York, applicable to agreements
made and to be performed in New York.

     9.  Severability.  Any provision of this  Agreement  which is prohibited or
unenforceable  in any  jurisdiction  shall be  ineffective to the extent of such
prohibition or unenforceability  without  invalidating the remaining  provisions
hereof in that  jurisdiction or affecting the validity or enforceability of such
provision in any other jurisdiction.


                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]


<PAGE>


     IN WITNESS  WHEREOF,  the parties  hereto have executed  this  Agreement or
caused it to be executed under seal by their duly authorized officers, all as of
the day and year first above written.

BORROWER:                   iPCS WIRELESS, INC.,
                            a Delaware corporation


                            By:  /s/ Alan B. Catherall
                                ----------------------------------------------
                            Name:    Alan B. Catherall
                                  --------------------------------------------
                            Title:   Chief Financial Officer
                                   -------------------------------------------

HOLDINGS:                   iPCS, INC., a Delaware corporation


                            By: /s/ Alan B. Catherall
                                ----------------------------------------------
                            Name:   Alan B. Catherall
                                  --------------------------------------------
                            Title:  Chief Financial Officer
                                   -------------------------------------------



EQUIPMENTCO:                iPCS EQUIPMENT, INC.,
                            a Delaware corporation


                            By: /s/ Alan B. Catherall
                                ----------------------------------------------
                            Name:   Alan B. Catherall
                                  --------------------------------------------
                            Title:  Chief Financial Officer
                                   -------------------------------------------

<PAGE>


ADMINISTRATIVE AGENT
AND LENDERS:                TORONTO DOMINION (TEXAS), INC.,
                            as Administrative Agent and as a Lender


                            By: /s/ Jeffrey R. Lents
                                ----------------------------------------------
                            Name:   Jeffrey R. Lents
                                  --------------------------------------------
                            Title:  Vice President
                                   -------------------------------------------

<PAGE>

                            GE CAPITAL CORPORATION, as a Lender


                            By:
                                ----------------------------------------------
                            Name:
                                  --------------------------------------------
                            Title:
                                   -------------------------------------------

<PAGE>

                            THE BANK OF NOVA SOCTIA, as a Lender


                            By: /s/ Stephen C. Levi
                                ----------------------------------------------
                            Name:   Steven C. Levi
                                  --------------------------------------------
                            Title:  Authorized Signatory
                                   -------------------------------------------

<PAGE>

                            BANK OF TOKYO-MITSUBISHI TRUST COMPANY, as a Lender


                            By: /s/ Michael J. Wiskind
                                ----------------------------------------------
                            Name:   Michael J. Wiskind
                                  --------------------------------------------
                            Title:  Vice President
                                   -------------------------------------------

<PAGE>

                            CITY NATIONAL BANK, as a Lender


                            By: /s/ Aaron Cohen
                                ----------------------------------------------
                            Name:   Aaron Cohen
                                  --------------------------------------------
                            Title:  Vice President
                                   -------------------------------------------

<PAGE>

                            FORTIS CAPITAL CORP., as a Lender


                            By: /s/ Alan E. McLintock
                                ----------------------------------------------
                            Name:   Alan E. McLintock
                                  --------------------------------------------
                            Title:  Managing Director
                                   -------------------------------------------


                            By:  /s/ Colm Kelly
                                ----------------------------------------------
                            Name:    Colm Kelly
                                  --------------------------------------------
                            Title:   Assistant Vice President
                                   -------------------------------------------

<PAGE>

                            IBM CREDIT CORPORATION, as a Lender


                            By: /s/ Thomas S. Curcio
                                ----------------------------------------------
                            Name:   Thomas S. Curcio
                                  --------------------------------------------
                            Title:  Manager of Credit
                                   -------------------------------------------

<PAGE>

                            NATIONAL CITY BANK, as a Lender


                            By: /s/ Chris Kalmbach
                                ----------------------------------------------
                            Name:   Chris Kalmbach
                                  --------------------------------------------
                            Title:  SVP
                                   -------------------------------------------

<PAGE>

                            PNC BANK, NATIONAL ASSOCIATION, as a Lender


                            By:
                                ----------------------------------------------
                            Name:
                                  --------------------------------------------
                            Title:
                                   -------------------------------------------