<PAGE>
                                                                  EXHIBIT 4.1(d)

              THIS DOCUMENT IS SUBJECT TO A CONFIDENTIAL TREATMENT
                      REQUEST PURSUANT TO RULE 24b-2 UNDER
                 THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED

                            AMENDMENT AGREEMENT NO. 4
                               TO CREDIT AGREEMENT

         THIS AMENDMENT AGREEMENT (this "Amendment Agreement") is made and
entered into as of this 16th day of November, 2001, by and among INSTEEL
INDUSTRIES, INC., a North Carolina corporation (herein called the "Borrower"),
BANK OF AMERICA, N.A., a national banking association (the "Agent"), as Agent
for the lenders (the "Lenders") party to the Credit Agreement dated January 31,
2000 as amended by the Amendment Agreement No. 1 to Credit Agreement dated
January 12, 2001, by the Supplement to Amendment Agreement No. 1 to the Credit
Agreement effective January 12, 2001, by the Amendment Agreement No. 2 to Credit
Agreement dated May 21, 2001 and by Amendment Agreement No. 3 to Credit
Agreement dated August 9, 2001 (collectively the "Agreement"), and the Equity
Appreciation Rights Agreement dated May 21, 2001 (the "EAR Agreement"), among
the Borrower, the Agent, and the Lenders, and the UNDERSIGNED LENDERS.


                              W I T N E S S E T H:


         WHEREAS, the parties hereto have entered into the Agreement pursuant to
which the Lenders have agreed to make loans to the Borrower as evidenced by the
Notes (as defined in the Agreement) and to issue Letters of Credit for the
benefit of the Borrower; and

         WHEREAS, as a condition to the making of the loans pursuant to the
Agreement the Lenders have required that the Subsidiaries of the Borrower
guarantee payment of all Obligations of the Borrower arising under the
Agreement; and

         WHEREAS, the Borrower has requested that the Lenders further amend the
Agreement and amend the EAR Agreement in the manner described herein; and

         WHEREAS, the Lenders are willing to further amend the Agreement and
amend the EAR Agreement subject to the terms and conditions set forth herein;

         NOW, THEREFORE, the Borrower, the Agent and the Lenders do hereby agree
as follows:

         1.       Definitions. The term "Agreement" as used herein and in the
Loan Documents (as defined in the Agreement) shall mean the Agreement as
hereinafter amended and modified. The term "EAR Agreement" as used herein and in
the Loan Documents (as defined in the Agreement) shall mean the EAR Agreement as
hereinafter amended and modified. Unless the context otherwise requires, other
than paragraph 7, all terms used herein without definition shall have the
definition provided therefor in the Agreement. Unless the context requires
otherwise, all


<PAGE>
terms used herein in paragraph 7 without definition shall have the definition
provided therefor in the EAR Agreement.

         2.       Amendment to Agreement. Subject to the conditions set forth
herein, the Agreement is hereby amended, effective as of the date of this
Amendment No. 4 as follows:

                  (a)      Section 1.01 is hereby amended by adding the
         following new definition thereto in the appropriate alphabetical order:

                           "Amendment No. 4" means Amendment Agreement No. 4 to
                  Credit Agreement and Equity Appreciation Rights Agreement
                  which Amendment No. 4 is dated November 16, 2001;

                  (b)      The definition of "Applicable Margin" in Section 1.1
         is hereby further amended in its entirety so that as amended it shall
         read as follows:

                           "`Applicable Margin' means for each of the periods
                  set forth below that percent per annum set forth opposite each
                  such period:

<TABLE>
<CAPTION>
                                                                  Applicable
                               Period                               Margin
                               ------                             ----------
                    <S>                                           <C>
                    Date of Amendment No. 4 through
                    December 31, 2001                              3.00%

                    January 1, 2002 through March 31, 2002         3.25%

                    April 1, 2002 through June 30, 2002            3.50%

                    July 1, 2002 through October 15, 2002          3.75%"
</TABLE>

                  (c)      The definition of "Stated Termination Date" in
         Section 1.1 is hereby further amended in its enti rety so that as
         amended it shall read as follows:

                           "`Stated Termination Date' means October 15, 2002."

                  (d)      The definition of "Term Loan Maturity Date" in
         Section 1.1 is hereby amended in its entirety so that as amended it
         shall read as follows:

                           "`Term Loan Maturity Date' means October 15, 2002."

                  (e)      The definition of "Total Revolving Credit Commitment"
         in Section 1.1 is hereby amended in its entirety so that as amended it
         shall read as follows:

                           "'Total Revolving Credit Commitment' means for the
                  period from the date of Amendment No. 4 through October 15,
                  2002 $50,000,000, subject to further reduction from time to
                  time in accordance with Section 2.2(e)."


                                       2
<PAGE>

                  (f)      Section 2.1(c) is hereby amended in its entirety so
         that as amended it shall read as follows:

                           "(c)     Payment of Principal. The principal amount
                  of the Term Loan shall be repaid in monthly installments on
                  the dates and in the amounts set forth below:

<TABLE>
<CAPTION>
                                    Date                               Amount
                                    ----                               ------
                                    <S>                                <C>
                                    April 30, 2002                     $300,000
                                    May 31, 2002                       $300,000
                                    June 30, 2002                      $300,000
                                    July 31, 2002                      $700,000
                                    August 31, 2002                    $700,000
                                    September 30, 2002                 $700,000
</TABLE>

                  provided, however, that the entire amount of Term Loan
                  Outstandings shall be due and payable in full on the Term Loan
                  Termination Date."

                  (g)      Clause (iii) of the first paragraph of Section 2.1(e)
         is hereby amended by (i) changing the reference to Section 10.6(c), (f)
         and (g) to refer to Section 10.6(b), (c), (f) and (g) and (ii) adding
         the following new sentence at the end of such paragraph:

                  "Notwithstanding the foregoing, the Net Proceeds received from
                  the sale of Inventory, other than in the ordinary course of
                  business, or Accounts Receivable shall be applied as
                  repayments of the Revolving Credit Outstandings to permanently
                  reduce the Total Revolving Credit Commitment."

                  (h)      Section 2.2(b) is hereby amended by deleting the last
         sentence thereof and inserting the following two sentences in lieu
         thereof:

                  "Each Advance under the Revolving Credit Facility, other than
                  Base Rate Refunding Loans, shall be in an amount of at least
                  $100,000, and, if greater than $100,000, an integral multiple
                  of $100,000. The Borrower shall not be entitled to request an
                  Advance more frequently than once each calendar week."

                  (i)      Section 9.1(i) is hereby amended in its entirety so
         that as amended it shall read as follows:

                           "(i)     as soon as practicable and in any event not
                  later than the last Business Day of each month during the
                  period from the date of Amendment No. 4 to the Facility
                  Termination Date deliver to the Agent and the Lenders a
                  monthly cash flow report and budget in form acceptable to the
                  Agent; and"

                  (j)      Section 9.1(j) is hereby amended by deleting the
         phrase "two weeks" appearing therein and inserting in lieu thereof the
         word "month".


                                       3
<PAGE>

                  (k)      Section 9.22 is hereby amended in its entirety so
         that as amended it shall read as follows:

                           "9.22. [*]. On or before November 30, 2001 engage, at
                  its cost and expense, a [*] acceptable to the Agent and the
                  Lenders in their sole discretion pursuant to the terms of an
                  agreement acceptable in form and substance to the Agent and
                  the Lenders in their sole discretion and have a [*] acceptable
                  to the Agent and the Lenders so engaged at all times."

                  (l)      Section 10.1(a) is hereby further amended in its
         entirety so that as amended it shall read as follows:

                           "(a)     Consolidated Net Worth. Permit Consolidated
                  Net Worth to be less than (i) $[*] and (ii) as at the last day
                  of each fiscal quarter of the Borrower ending after September
                  29, 2001 and until (but excluding) the last day of the next
                  following fiscal quarter of the Borrower, the sum of (A) the
                  amount of Consolidated Net Worth required to be maintained
                  pursuant to this Section 10.1(a) as at the end of the
                  immediately preceding fiscal quarter (or, in the case of the
                  computation for the quarter ended December 29, 2001, $[*]),
                  plus (B) 50% of Consolidated Net Income (with no reduction for
                  net losses during any period) for the fiscal quarter of the
                  Borrower ending on such day (including within "Consolidated
                  Net Income" certain items otherwise excluded, as provided for
                  in the definition of "Consolidated Net Income"), plus (C) 100%
                  of the aggregate amount of all increases in the stated capital
                  and additional paid-in capital accounts of the Borrower
                  resulting from the issuance of equity securities or other
                  capital investments."

                  (m)      The table in Section 10.1(b) is amended in its
         entirety so that as amended it shall read as follows:


<TABLE>
<CAPTION>
                                        Period                                  Amount
                                        ------                                  ------
                           <S>                                                  <C>
                           1st fiscal quarter of Fiscal Year 2002               $[*]
                           2nd fiscal quarter of Fiscal Year 2002               $[*]
                           3rd fiscal quarter of Fiscal Year 2002               $[*]
                           4th fiscal quarter of Fiscal Year 2002               $[*]

</TABLE>

                  (n)      Clause (b) of Section 10.6 is amended in its entirety
         so that as amended it shall read as follows:

                           "(b)     the sale or transfer of assets associated
                                    with facilities of Borrower or its
                  Subsidiaries so long as the Net Proceeds are paid to the
                  Lenders as provided in Section 2.1(e) and such Net Proceeds
                  are not less than 90% of the forced liquidation value of such
                  assets as determined based upon appraisals currently in the
                  possession of the Agent;"

         [*] Confidential portion has been omitted and filed separately with the
Commission.


                                       4
<PAGE>

         3.       Swing Line. From and after the date of this Amendment
Agreement the Borrower shall not be entitled to request Swing Line Loans, the
Swing Line shall terminate as of the date of this Amendment Agreement and the
Borrower shall have paid in full all Swing Line Outstandings.

         4.       Subsidiary Consents. Each Subsidiary of the Borrower that has
delivered a Guaranty to the Agent has joined in the execution of this Amendment
Agreement for the purpose of (i) agreeing to the amendment to the Agreement and
(ii) confirming its guarantee of payment of all the Obligations.

         5.       Representations and Warranties. The Borrower hereby represents
and warrants that:

                  (a)      The representations and warranties made by Borrower
         in Article VIII of the Agreement are true on and as of the date hereof
         except that the financial statements referred to in Section 8.6(a)
         shall be those most recently furnished to each Lender pursuant to
         Section 9.1;

                  (b)      There has been no material adverse change in the
         condition, financial or otherwise, of the Borrower and its Subsidiaries
         since the date of the most recent financial reports of the Borrower
         received by each Lender under Section 9.1 thereof, other than changes
         in the ordinary course of business, none of which has been a material
         adverse change;

                  (c)      The business and properties of the Borrower and its
         Subsidiaries are not and have not been adversely affected in any
         substantial way as the result of any fire, explosion, earthquake,
         accident, strike, lockout, combination of workers, flood, embargo,
         riot, activities of armed forces, war or acts of God or the public
         enemy, or cancellation or loss of any major contracts; and

                  (d)      After giving effect to this Amendment Agreement
         (including the waivers by the Lenders set forth herein), no event has
         occurred and no condition exists which, upon the consummation of the
         transaction contemplated hereby, constitutes a Default or an Event of
         Default on the part of the Borrower under the Agreement, the Notes or
         any other Loan Document either immediately or with the lapse of time or
         the giving of notice, or both.

         6.       Deferral of Amendment Fee under Amendment No. 2. The
provisions regarding the Amendment Fee as set forth in paragraph 7 of Amendment
No. 2 are modified as follows: (i) payment of $[*] is due on each of January 31,
2002, April 30, 2002 and July 31, 2002 and (ii) payment of $[*] is due on
October 15, 2002. In the event all Obligations have been paid in full prior to
the date each payment shall be due, payment of such fees shall be waived.

         [*] Confidential portion has been omitted and filed separately with the
Commission.


                                       5
<PAGE>

         7.       Amendment to EAR Agreement. Subject to the conditions set
forth herein, the EAR Agreement is hereby amended, effective as of the date of
this Amendment No. 4 as follows:

                  (a)      Section 1.01 is hereby amended by adding the
         following new definition thereto in the appropriate alphabetical order:

                           "Amendment No. 4" means Amendment Agreement No. 4 to
                  Credit Agreement and Equity Appreciation Rights Agreement
                  which Amendment No. 4 is dated November 16, 2001;"

                  (b)      The definition of "Exercise Period" in Section 1.01
         is hereby amended in its entirety so that as amended it shall read as
         follows:

                           "'Exercise Period" means the period (a) beginning and
                  ending in the case of Section 2.02(b) and (c), upon payment in
                  full of all the Loans or (b) beginning on the earlier to occur
                  of (i) July 15, 2002 or (ii) occurrence of an Event of Default
                  under the Credit Agreement and ending on July 15, 2004;"

                  (c)      Section 2.02(b) is hereby amended in its entirety so
         that as amended it shall read as follows:

                           "(b) In the event all Obligations (as defined in the
                  Credit Agreement) have been paid in full by April 15, 2002 and
                  the Facility Termination Date (as defined in the Credit
                  Agreement) shall have occurred by April 15, 2002, the Rights
                  Fee shall be $[*];"

                  (d)      Section 2.02(c) is hereby amended in its entirety so
         that as amended it shall read as follows:

                           "(c) In the event all Obligations (as defined in the
                  Credit Agreement) have not been paid in full by April 15, 2002
                  but are paid in full by July 15, 2002 and the Facility
                  Termination Date (as defined in the Credit Agreement) shall
                  have occurred by July 15, 2002, the Rights Fee shall be in a
                  maximum amount of $[*] but in no event less than the greater
                  of"

                           (i)      [*]; or
                           (ii)     $[*]; and

         8.       Conditions. This Amendment Agreement shall become effective
upon the Borrower delivering or causing to be delivered to the Agent the
following:

                  (i)      five (5) counterparts of this Amendment Agreement
         duly executed by the Borrower, the Agent and the Required Lenders and
         consented to by each of the Subsidiaries;

         [*] Confidential portion has been omitted and filed separately with the
Commission.


                                       6
<PAGE>

                  (ii)     copy of resolutions adopted by the Board of Directors
         of the Borrower and each Guarantor approving this Amendment Agreement
         and authorizing its execution certified by the Secretary or Assistant
         Secretary to be a true and correct copy duly adopted;

                  (iii)    all other fees and expenses due in connection with
         this Amendment Agreement;

         9.       Acknowledgment; Release. The Borrower and the Guarantors
acknowledge that they have no existing defense, counterclaim, offset,
cross-complaint, claim or demand of any kind or nature whatsoever that can be
asserted to reduce or eliminate all or any part of any of their respective
liability to pay the full indebtedness outstanding under the terms of the
Agreement and any other Loan Documents which evidence, guaranty or secure the
Obligations. The Borrower and the Guarantors hereby release and forever
discharge the Agent, the Lenders and all of their officers, directors,
employees, attorneys, consultants and agents from any and all actions, causes of
action, debts, dues, claims, demands, liabilities and obligations of every kind
and nature, both in law and in equity, known or unknown, whether matured or
unmatured, absolute or contingent.

         10.      Costs and Expenses. The Borrower agrees to pay all costs and
expenses associated with the preparation, due diligence, administration and
enforcement of all documentation executed in connection with the Amendment
Agreement, including without limitation, the legal fees and out-of-pocket
expenses of counsel to the Agent. The Borrower also agrees to pay the expenses
of the Agent and the Lenders in connection with Collateral review, field audits
and retention of consultants.

         11.      Entire Agreement. This Amendment Agreement sets forth the
entire understanding and agreement of the parties hereto in relation to the
subject matter hereof and supersedes any prior negotiations and agreements among
the parties relative to such subject matter. No promise, conditions,
representation or warranty, express or implied, not herein set forth shall bind
any party hereto, and no one of them has relied on any such promise, condition,
representation or warranty. Each of the parties hereto acknowledges that, except
as in this Amendment Agreement otherwise expressly stated, no representations,
warranties or commitments, express or implied, have been made by any other party
to the other. None of the terms or conditions of this Amendment Agreement may be
changed, modified, waived or canceled orally or otherwise, except by writing, in
the manner provided in the Agreement, specifying such change, modification,
waiver or cancellation of such terms or conditions, or of any proceeding or
succeeding breach thereof.

         12.      Full Force and Effect of Agreement. Except as hereby
specifically amended, modified or supplemented, the Agreement and all of the
other Loan Documents are hereby confirmed and ratified in all respects and shall
remain in full force and effect according to their respective terms.

                  [Remainder of page intentionally left blank.]


                                       7
<PAGE>


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

                                         BORROWER:

                                         INSTEEL INDUSTRIES, INC.
WITNESS:

/s/ Gary D. Kniskern                     By:      /s/ H.O. Woltz III
--------------------------------                 ------------------------------
Print Name: Gary D. Kniskern             Name:   H.O. Woltz III
            --------------------                 ------------------------------
                                         Title:   President
                                                 ------------------------------
/s/ Michael C. Gazmarian
--------------------------------
Print Name: Michael C. Gazmarian
            --------------------



                                       8
<PAGE>


                                            GUARANTORS:

                                            INSTEEL WIRE PRODUCTS COMPANY
                                            INTERCONTINENTAL METALS CORPORATION
                                            FLORIDA WIRE AND CABLE, INC.

WITNESS:

/s/ Gary D. Kniskern                        By:     /s/ H.O. Woltz III
------------------------------------              -----------------------------
Print Name: Gary D. Kniskern                Name:   H.O. Woltz III
            ------------------------              -----------------------------
                                            Title:  President
                                                  -----------------------------
/s/ Michael C. Gazmarian
------------------------------------
Print Name: Michael C. Gazmarian
            ------------------------


                                       9
<PAGE>
                                 BANK OF AMERICA, N.A., as Agent for the Lenders



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



                                 BANK OF AMERICA, N.A., as a Lender



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


                                       10



<PAGE>


                               BRANCH BANKING AND TRUST COMPANY



                               By:    /s/ Richard C.F. Spencer
                                      -----------------------------------------
                               Name:  Richard C.F. Spencer
                                      -----------------------------------------
                               Title: Senior Vice President
                                      -----------------------------------------


                                       11

<PAGE>


                                  FIRST UNION NATIONAL BANK



                                  By:    /s/ H. Leon McGee
                                         --------------------------------------
                                  Name:  H. Leon McGee
                                         --------------------------------------
                                  Title: Senior Vice President
                                         --------------------------------------


                                       12

<PAGE>


                                  NATIONAL BANK OF CANADA



                                  By:    /s/ Bill Handley/Alex M. Council IV
                                         ---------------------------------------
                                  Name:  Bill Handley/Alex Council IV
                                         ---------------------------------------
                                  Title: Vice President & Manager/Vice President
                                         ---------------------------------------


                                       13