<PAGE>
                                                                    EXHIBIT 4(b)

                        AMENDMENT NO. 1 TO NOTE AGREEMENT

                          Dated as of December 17, 2003

                  This AMENDMENT NO. 1 (the "Amendment") is entered into by and
among Guilford Mills, Inc. (the "Company") as Borrower, the Guarantors referred
to in the Note Agreement (as defined below), and the Noteholders referred to in
the Note Agreement.

                              PRELIMINARY STATEMENT

                  A.       The Company, the Guarantors, and the Noteholders have
entered into that certain Note Agreement dated as of October 1, 2002 (as
amended, restated, modified and waived from time to time, the "Note Agreement";
the terms defined therein being used herein as therein defined unless otherwise
defined herein).

                  B.       The Company has informed the Noteholders of its
intention to sell the capital stock of one or more of the following wholly owned
subsidiaries: (i) Grupo Ambar, S.A. de C.V., (ii) American Textil, S.A. de C.V.,
and (iii) Servicios Corporativos Ambar, S.A. de C.V (such transaction, the
"Sale").

                  C.       The Company and the Guarantors have requested, and
the Noteholders have agreed, to amend the Note Agreement as hereinafter set
forth to allow, among other things, for consummation of the Sale.

SECTION 1.        Amendments to Note Agreement.  Upon the occurrence of the
First Amendment Effective Date (as defined herein), the Note Agreement is hereby
amended as follows:

         (a)      Section 7.4(b) of the Note Agreement is hereby amended by
inserting the following clause (w) immediately preceding clause (x) therein:

                  "(w) result from the disposition of life insurance policies of
                  former employees as a result of the surrender of such policies
                  on or before October 31, 2003 in an amount not to exceed
                  $167,043.63,"

         (b)      Section 9.2(a) of the Note Agreement is hereby amended by (i)
deleting the word "and" at the end of clause (g) thereof, (ii) deleting the "."
at the end of clause (h) thereof and inserting in lieu thereof "; and" and (iii)
adding the following new clause (i):

         (i) the sale or other disposition of all the capital stock of one or
         more of the following Subsidiaries: (x) Grupo Ambar, S.A. de C.V., (y)
         American Textil, S.A. de C.V., or (z) Servicios Corporativos Ambar,
         S.A. de C.V., pursuant to the terms substantially similar to those set
         forth in that certain term sheet dated October 2, 2003 (the "Term
         Sheet") delivered to the Noteholders shall be authorized.
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         (c)      The definition of "Minimum Consolidated Tangible Net Worth"
set forth in Section 9.11 of the Note Agreement is hereby amended by inserting
the following at the end thereof:

                  "provided that, any reduction in Minimum Consolidated Tangible
                  Net Worth of up to $16,000,000 resulting solely from the
                  disposition of (i) Grupo Ambar, S.A. de C.V., (ii) American
                  Textil, S.A. de C.V., or (iii) Servicios Corporativos Ambar,
                  S.A. de C.V. shall not be taken into account when calculating
                  compliance with Section 9.11.

SECTION 2.        Release of Pledged Collateral. In accordance with Section 3.10
of the Guaranty, Security and Pledge Agreement dated October 1, 2002 (the
"Security Agreement"), and Section 8.8(b) of the Note Agreement, each Noteholder
agrees that upon consummation of the Sale, its lien on the capital stock of any
of Grupo Ambar, S.A., de C.V., American Textil, S.A. de C.V. or Servicios
Corporativos Ambar, S.A. de C.V., shall terminate and Wachovia Bank, National
Association, as Collateral Agent (the "Collateral Agent"), shall be authorized
to release the security interest thereon.

SECTION 3.        Certifications of Company Under Note Agreement: In accordance
with Section 8.8(b) of the Note Agreement, the Company hereby certifies that (a)
the provisions of Section 9.2 of the Note Agreement (as amended hereby) will not
be breached by the Sale; (b) except as otherwise contemplated by the terms of
the Sale as set forth in the Term Sheet, all loans to Grupo Ambar, S.A., de
C.V., American Textil, S.A. de C.V. or Servicios Corporativos Ambar, S.A. de
C.V. from the Company or any other Guarantor have been satisfied in full; (c)
the net purchase price (recognizing that the purchase price consists of non-cash
consideration) to be realized by the Company from the sale of any of Grupo
Ambar, S.A., de C.V., American Textil, S.A. de C.V. or Servicios Corporativos
Ambar, S.A. de C.V., will not be less than 100% of the Fair Market Value of each
such subsidiary actually sold in the Sale, as determined in good faith by the
Company's board of directors; and (d) no Event of Default is in existence or
will be caused as a result of the Sale.

SECTION 4.        Exclusion of TaxLLC from Pledged Collateral. It is hereby
acknowledged and agreed by the parties hereto that TaxLLC (as defined in the
Term Sheet) is being created solely for the purpose of effectuating the Sale
and, accordingly, TaxLLC shall not be deemed Pledged Collateral (as defined in
the Security Agreement) and shall not be deemed a Guarantor pursuant to Section
8.7 of the Note Agreement; provided that the Sale shall occur substantially
simultaneously with (i) the transfer of the capital stock of any of Grupo Ambar,
S.A., de C.V., American Textil, S.A. de C.V. or Servicios Corporativos Ambar,
S.A. de C.V. into TaxLLC, as more fully described in the Term Sheet and (ii) the
release of the stock as described in Section 2 above.

SECTION 5.        Conditions of Effectiveness. This Amendment shall become
effective on the date (such date, the "First Amendment Effective Date") upon
which (i) the Collateral Agent shall have received counterparts of this
Amendment executed by the Company, the Guarantors and the Required Holders,
(ii) receipt by King & Spalding LLP, as counsel to the Noteholders, of a copy
of a similar amendment executed and delivered by the Company and the Required
Lenders under the Credit, Security, Guaranty and Pledge Agreement, dated as of
October 1, 2002


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<PAGE>

(the "Credit Agreement"), and (iii) the Company shall have paid to King &
Spalding LLP, as counsel to the Noteholders, all costs and expenses (including
legal fees) for services rendered to the Noteholders through the date of this
Amendment.

SECTION 6.        Restatement of Representations and Warranties. The Company
hereby restates and renews each and every representation and warranty heretofore
made by it in the Note Agreement and the other Related Documents as fully as if
made on the date hereof (but after giving effect to the amendments contained
herein) and with specific reference to this Amendment.

SECTION 7.        Reference to and Effect on the Related Documents. (a) Upon the
occurrence of the First Amendment Effective Date, each reference in the Note
Agreement to "this Agreement," "hereunder," "hereof," "herein" or words of like
import, and each reference in any Related Documents, shall mean and be a
reference to the Note Agreement or such other Related Document as amended
hereby.

         (b)      Except as specifically amended above, the Note Agreement and
the other Related Documents shall remain in full force and effect and are hereby
ratified and confirmed. Without limiting the generality of the foregoing, and
except as expressly provided for in Section 2 of this Amendment, all of the
"Collateral" described therein does and shall continue to secure the payment of
all Secured Obligations.

         (c)      The execution, delivery and effectiveness of this Amendment
shall not, except as expressly provided herein, operate as a waiver of any
right, power or remedy of any Noteholder under any of the Related Documents, nor
constitute a waiver of any provision of any of the Related Documents.

         (d)      The Required Holders are under no obligation to enter into
this Amendment. The Required Holders entering into this Amendment shall not be
deemed to create or infer a course of dealing between any Noteholder, the
Company or any of the Guarantors with regard to any provision of the Note
Agreement.

SECTION 8.        Costs, Expenses and Taxes. The Company and Guarantors jointly
and severally agree to pay on demand all costs and expenses of the Noteholders
in connection with the preparation, execution and delivery of this Amendment and
the other instruments and documents to be delivered hereunder, including,
without limitation, the reasonable fees and out-of-pocket expenses of counsel
for the Noteholders with respect thereto and with respect to advising the
Noteholders as to their rights and responsibilities hereunder and thereunder.
The Company and Guarantors further jointly and severally agree to pay on demand
all costs and expenses, if any (including, without limitation, reasonable
counsel fees and expenses), in connection with the enforcement (whether through
negotiations, legal proceedings or otherwise) of this Amendment and the other
instruments and documents to be delivered hereunder, including, without
limitation, reasonable counsel fees and expenses in connection with the
enforcement of rights under this Section 8. In addition, the Company and
Guarantors shall pay any and all stamp and other taxes payable or determined to
be payable in connection with the execution and delivery of this Amendment and
the other instruments and documents to be


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delivered hereunder, and agree to save the Noteholders harmless from and against
any and all liabilities with respect to or resulting from any delay in paying or
omission to pay such taxes.

SECTION 9.        Execution in Counterparts. This Amendment may be executed in
any number of counterparts and by different parties hereto in separate
counterparts, each of which when so executed and delivered shall be deemed to be
an original and all of which taken together shall constitute but one and the
same instrument.

SECTION 10.       Governing Law. This Amendment shall be governed by, and
construed in accordance with, the laws of the State of New York.


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                                                          8
                  IN WITNESS WHEREOF, the Company, the Guarantors, and the
Required Holders have caused this Amendment to be executed by their respective
officers thereunto duly authorized, as of the date first above written.

                                    ISSUER:

                                    GUILFORD MILLS, INC.


                                        By: /s/ Robert A. Emken, Jr.
                                            ------------------------------------
                                            Name: Robert A. Emken, Jr.
                                            Title: General Counsel

                                    GUARANTORS:

                                    CURTAINS AND FABRICS, INC.
                                    GOLD MILLS, INC.
                                    RASCHEL FASHION INTERKNITTING, LTD.
                                    GFD FABRICS, INC.
                                    GFD SERVICES, INC.
                                    HOFMANN LACES, LTD.
                                    ADVISORY RESEARCH SERVICES, INC.
                                    GUILFORD MILLS (MICHIGAN), INC.
                                    GUILFORD AIRMONT, INC.
                                    GOLDMILLS FARMS, INC.
                                    GMI COMPUTER SALES, INC.


                                        By: /s/ Robert A. Emken, Jr.
                                            ------------------------------------
                                            Name: Robert A. Emken, Jr.
                                            Title: General Counsel

                                         -and-

                                    TWIN RIVERS TEXTILE PRINTING
                                    & FINISHING

                                    By: Guilford Mills, Inc., as general partner

                                        By: /s/ Robert A. Emken, Jr.
                                            ------------------------------------
                                            Name: Robert A. Emken, Jr.
                                            Title: General Counsel


                                       5
<PAGE>

                                NOTEHOLDERS:

                                THE PRUDENTIAL INSURANCE COMPANY OF AMERICA


                                    By: /s/ Paul G. Price
                                        ----------------------------------------
                                        Name: Paul G. Price
                                        Title:  Vice President

                                MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY


                                    By: /s/ Steven J. Katz
                                        ----------------------------------------
                                        Name: Steven J. Katz
                                        Title: Second Vice President & Associate
                                                 General Counsel

                                C.M. LIFE INSURANCE COMPANY


                                    By: /s/ Richard C. Morrison
                                        ----------------------------------------
                                        Name: Richard C. Morrison
                                        Title:  Managing Director

                                WACHOVIA BANK, NATIONAL ASSOCIATION,


                                    By: /s/ Colleen McCullum
                                        ----------------------------------------
                                        Name: Colleen McCullum
                                        Title: Managing Director

                                BANK ONE, NA


                                    By: /s/ C. Dianne Wooley
                                        ----------------------------------------
                                        Name: C. Dianne Wooley
                                        Title: First Vice President


                                       6
<PAGE>

                                GENERAL ELECTRIC CAPITAL CORPORATION


                                    By: /s/ Patrick E. Flynn
                                        ----------------------------------------
                                        Name: Patrick E. Flynn
                                        Title: Risk Manager

                                CARL MARKS STRATEGIC INVESTMENTS, L.P.


                                    By: /s/ James F. Wilson
                                        ----------------------------------------
                                        Name: James F. Wilson
                                        Title: General Partner


                                CARL MARKS STRATEGIC INVESTMENTS III, L.P.


                                    By: /s/ James F. Wilson
                                        ----------------------------------------
                                        Name: James F. Wilson
                                        Title: General Partner


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