<PAGE>   1
    AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 29, 1998
                                                      REGISTRATION NO. 333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                              --------------------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                              --------------------

                              SCHUFF STEEL COMPANY
               (EXACT NAME OF REGISTRANT AS SPECIFIED IN CHARTER)

            DELAWARE                                             86-0318760
  (STATE OR OTHER JURISDICTION                                (I.R.S. EMPLOYER
OF INCORPORATION OR ORGANIZATION)                            IDENTIFICATION NO.)

                              --------------------

                 1841 W. BUCHANAN STREET, PHOENIX, ARIZONA 85009
               (ADDRESS OF PRINCIPAL EXECUTIVE OFFICE) (ZIP CODE)

                              --------------------

              SCHUFF STEEL COMPANY 1998 DIRECTOR COMPENSATION PLAN
                              (FULL TITLE OF PLAN)

                              --------------------

                                 SCOTT A. SCHUFF
                              SCHUFF STEEL COMPANY
                             1841 W. BUCHANAN STREET
                             PHOENIX, ARIZONA 85009
                     (NAME AND ADDRESS OF AGENT FOR SERVICE)

                                 (602) 252-7787
          (TELEPHONE NUMBER, INCLUDING AREA CODE, OF AGENT FOR SERVICE)

                              --------------------

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
================================================================================================
                                       PROPOSED MAXIMUM       PROPOSED MAXIMUM       AMOUNT OF
TITLE OF SECURITIES   AMOUNT TO BE         OFFERING          AGGREGATE OFFERING     REGISTRATION
 TO BE REGISTERED      REGISTERED     PRICE PER SHARE(1)          PRICE(1)              FEE
------------------------------------------------------------------------------------------------
<S>                   <C>             <C>                    <C>                    <C>
Common Stock             50,000             $6.125                $306,250              $85
$0.001 par value
================================================================================================
</TABLE>

================================================================================

(1)      ESTIMATED SOLELY FOR THE PURPOSE OF CALCULATING THE AMOUNT OF THE
         REGISTRATION FEE, PURSUANT TO RULES 457(c) AND 457(h) OF THE SECURITIES
         ACT OF 1933 (THE "SECURITIES ACT"), ON THE BASIS OF THE AVERAGE OF THE
         HIGH AND LOW PRICES OF THE REGISTRANT'S COMMON STOCK ON OCTOBER 29,
         1998.


                             Exhibit Index on Page 7
<PAGE>   2
                                     PART I
              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

         The documents containing the information specified in Part I, Items 1
and 2, will be delivered to participants in accordance with Form S-8 and Rule
428 under the Securities Act of 1933, as amended (the "Securities Act"). These
documents and the documents incorporated by reference into this Registration
Statement pursuant to Item 3 of Part II of this Registration Statement, taken
together, constitute a prospectus that meets the requirements of Section 10(a)
of the Securities Act.

                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents have been filed by Schuff Steel Company (the
"Registrant") with the Securities and Exchange Commission pursuant to the
Securities Exchange Act of 1934 and are hereby incorporated by reference into
this Registration Statement:

         (a)      The Registrant's Annual Report on Form 10-K for the fiscal
                  year ended December 31, 1997;

         (b)      The Registrant's Quarterly Report on Form 10-Q for the fiscal
                  quarter ended March 31, 1998;

         (c)      The Registrant's Quarterly Report on Form 10-Q for the fiscal
                  quarter ended June 30, 1998;

         (d)      The Registrant's Current Report on Form 8-K dated May 12,
                  1998;

         (e)      The Registrant's Current Report on Form 8-K, as amended, dated
                  June 4, 1998;

         (f)      The Registrant's Current Report on Form 8-K dated August 12,
                  1998;

         (g)      The Registrant's Current Report on Form 8-K dated August 31,
                  1998;

         (h)      The Registrant's Current Report on Form 8-K dated October 15,
                  1998; and

         (i)      The description of the Registrant's capital stock contained in
                  the Registrant's Registration Statement on Form 8-A, dated
                  June 17, 1997, filed with the Securities and Exchange
                  Commission pursuant to Section 12(g) of the Securities Act of
                  1934.

         All documents subsequently filed by the Registrant pursuant to Sections
13(a), 13(c), 14, or 15(d) of the Securities Exchange Act of 1934, prior to the
filing of a post-effective amendment which indicates that all securities offered
have been sold or which deregisters all securities then remaining unsold, shall
be deemed to be incorporated by reference in this Registration Statement and to
be a part hereof from the date of filing such documents. Any statement contained
in a document incorporated or deemed to be incorporated by reference herein
shall be deemed to be modified or superseded for purposes of this Registration
Statement to the extent that a statement contained herein or in any subsequently
filed document which also is or is deemed to be incorporated by reference herein
modifies or supersedes such statement. Any statement so modified or superseded
shall not be deemed, except as so modified or superseded, to constitute a part
of this Registration Statement.

ITEM 4.  DESCRIPTION OF SECURITIES.  Not applicable.


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<PAGE>   3
ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.  Not applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         The Company's Certificate of Incorporation provides that a director of
the Company shall not be personally liable to the corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director,
except for liability for: (i) any breach of the director's duty of loyalty to
the Company or its stockholders; (ii) acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law; (iii)
liability for payments of dividends or stock purchases or redemptions in
violation of Section 174 of the Delaware General Corporation Law; or (iv) any
transaction from which the director derived an improper personal benefit. In
addition, the Company's Certificate of Incorporation provides that the Company
shall to the fullest extent authorized by the Delaware General Corporation Law,
as the same exists or may hereafter be amended (but, in the case of any such
amendment, only to the extent that such amendment permits the corporation to
provide broader indemnification rights than such law permitted the corporation
to provide prior to such amendment), indemnify and hold harmless any person who
was or is a party, or is threatened to be made a party to or is otherwise
involved in any threatened, pending or completed action, suit or proceeding,
whether civil, criminal, administrative or investigative by reason of the fact
that such person is or was a director or officer of the corporation, or is or
was serving at the request of the corporation as a director, officer, employee
or agent of another corporation, partnership, joint venture, trust or other
enterprise, including service with respect to an employee benefit plan
(hereinafter an "Indemnitee") against expenses, liabilities and losses
(including attorneys' fees, judgments, fines, excise taxes or penalties paid in
connection with the Employee Retirement Income Security Act of 1974, as amended,
and amounts paid in settlement) reasonably incurred or suffered by such
Indemnitee in connection therewith; provided, however, that except as otherwise
provided with respect to proceedings to enforce rights to indemnification, the
Company shall indemnify any such Indemnitee in connection with a proceeding (or
part thereof) initiated by such Indemnitee only if such proceeding or part
thereof was authorized by the board of directors of the Company.

         The right to indemnification set forth above includes the right to be
paid by the Company the expenses (including attorneys' fees) incurred in
defending any such proceeding in advance of its final disposition; provided,
however, that, if the Delaware General Corporation Law requires, an advancement
of expenses incurred by an Indemnitee in his capacity as a director or officer
(and not in any other capacity in which service was or is rendered by such
Indemnitee, including, without limitation, service to an employee benefit plan)
shall be made only upon delivery to the Company of an undertaking, by or on
behalf of such Indemnitee, to repay all amounts so advanced if it shall
ultimately be determined by final judicial decision from which there is not
further right to appeal that such Indemnitee is not entitled to be indemnified
for such expenses under this section or otherwise. The rights to indemnification
and to the advancement of expenses conferred herewith are contract rights and
continue as to an Indemnitee who has ceased to be a director, officer, employee
or agent and inures to the benefit of the Indemnitee's heirs, executors and
administrators.

         The Delaware General Corporation Law provides that indemnification is
permissible only when the director, officer, employee, or agent acted in good
faith and in a manner reasonably believed to be in or not opposed to the best
interests of the Company, and, with respect to any criminal action or
proceeding, had no reasonable cause to believe the conduct was unlawful. The
Delaware General Corporation Law also precludes indemnification in respect of
any claim, issue, or matter as to which an officer, director, employee, or agent
shall have been adjudged to be liable to the Company unless and only to the
extent that the Court of Chancery or the court in which such action or suit was
brought shall determine that, despite such adjudication of liability but in view
of all the circumstances of the case, such person is fairly and reasonably
entitled to indemnity for such expenses which the Court of Chancery or such
other court shall deem proper.


                                        3
<PAGE>   4
ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.  Not applicable.

ITEM 8.  EXHIBITS.

             Exhibit No.      Description
             -----------      -----------

                 5            Opinion of Snell & Wilmer L.L.P.
                 23.1         Consent of Ernst & Young LLP, Independent Auditors
                 23.2         Consent of Mauldin & Jenkins, LLC
                 23.3         Consent of Snell & Wilmer L.L.P.

ITEM 9.  UNDERTAKINGS.

         (a)  The undersigned Registrant hereby undertakes:

                  (1)      To file, during any period in which offers or sales
                           are being made, a post-effective amendment to this
                           registration statement:

                           (i)      To include any prospectus required by
                                    section 10(a)(3) of the Securities Act of
                                    1933;

                           (ii)     To reflect in the prospectus any facts or
                                    events arising after the effective date of
                                    the registration statement (or the most
                                    recent post-effective amendment thereof)
                                    which, individually or in the aggregate,
                                    represent a fundamental change in the
                                    information set forth in the registration
                                    statement. Notwithstanding the foregoing,
                                    any increase or decrease in volume of
                                    securities offered (if the total dollar
                                    value of securities offered would not exceed
                                    that which was registered) and any deviation
                                    from the low or high end of the estimated
                                    maximum offering range may be reflected in
                                    the form of prospectus filed with the
                                    Commission pursuant to Rule 424(b) if, in
                                    the aggregate, the changes in volume and
                                    price represent no more than 20 percent
                                    change in the maximum aggregate offering
                                    price set forth in the "Calculation of
                                    Registration Fee" table in the effective
                                    registration statement;

                           (iii)    To include any material information with
                                    respect to the plan of distribution not
                                    previously disclosed in the registration
                                    statement or any material change to such
                                    information in the registration statement;

                           provided, however, that paragraphs (a)(1)(i) and
                           (a)(1)(ii) do not apply if the registration statement
                           is on Form S-3, Form S-8 or Form F-3, and the
                           information required to be included in a
                           post-effective amendment by those paragraphs is
                           contained in periodic reports filed with or furnished
                           to the Commission by the Registrant pursuant to
                           Section 13 or Section 15(d) of the Securities
                           Exchange Act of 1934 that are incorporated by
                           reference in the registration statement.

                  (2)      That, for the purpose of determining any liability
                           under the Securities Act of 1933, each such
                           post-effective amendment shall be deemed to be a new
                           registration statement relating to the securities
                           offered therein, and the offering of such securities
                           at that time shall be deemed to be the initial bona
                           fide offering thereof.


                                        4
<PAGE>   5
                  (3)      To remove from registration by means of a
                           post-effective amendment any of the securities being
                           registered which remain unsold at the termination of
                           the offering.

         (b)      The undersigned Registrant hereby undertakes that, for
                  purposes of determining any liability under the Securities Act
                  of 1933, each filing of the Registrant's annual report
                  pursuant to Section 13(a) or Section 15(d) of the Securities
                  Exchange Act of 1934 (and, where applicable, each filing of an
                  employee benefit plan's annual report pursuant to Section
                  15(d) of the Securities Exchange Act of 1934) that is
                  incorporated by reference in the registration statement shall
                  be deemed to be a new registration statement relating to the
                  securities offered therein, and the offering of such
                  securities at that time shall be deemed to be the initial bona
                  fide offering thereof.

         (c)      Insofar as indemnification for liabilities arising under the
                  Securities Act of 1933 may be permitted to directors, officers
                  and controlling persons of the Registrant pursuant to the
                  foregoing provisions, or otherwise, the Registrant has been
                  advised that in the opinion of the Securities and Exchange
                  Commission such indemnification is against public policy as
                  expressed in such Act and is, therefore, unenforceable. In the
                  event that a claim for indemnification against such
                  liabilities (other than payment by the Registrant of expenses
                  incurred or paid by a director, officer or controlling person
                  of the Registrant in the successful defense of any action,
                  suit or proceeding) is asserted by such director, officer or
                  controlling person in connection with the securities being
                  registered, the Registrant will, unless in the opinion of its
                  counsel the matter has been settled by controlling precedent,
                  submit to a court of appropriate jurisdiction the question
                  whether such indemnification by it is against public policy as
                  expressed in the Act and will be governed by the final
                  adjudication of such issue.


                                        5
<PAGE>   6
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Phoenix, State of Arizona, on October 29, 1998.

                                    SCHUFF STEEL COMPANY, a Delaware corporation

                                    By: /s/ Scott A. Schuff
                                        ----------------------------------------
                                        Scott A. Schuff
                                        President and Chief Executive Officer

         Pursuant to the requirements of the Securities Act of 1933, this
registration statement has been signed by the following persons in the
capacities and on the date indicated.

<TABLE>
<CAPTION>
Name and Signature               Title                                   Date
------------------               -----                                   ----
<S>                              <C>                                     <C> 
/s/ David A. Schuff              Chairman of the Board of Directors      October 29, 1998
-----------------------------
David A. Schuff

/s/ Scott A. Schuff              President, Chief Executive Officer      October 29, 1998
-----------------------------    and Director                   
Scott A. Schuff                  (Principal Executive Officer)
                                   
/s/ Kenneth F. Zylstra           Vice President, Chief Financial         October 29, 1998
-----------------------------    Officer and Director  
Kenneth F. Zylstra               (Principal Financial and Accounting
                                 Officer)  
                                 

/s/ Edward M. Larson             Director                                October 29, 1998
-----------------------------
Edward M. Larson

/s/ Dennis DeConcini             Director                                October 29, 1998
-----------------------------
Dennis DeConcini
</TABLE>


                                        6
<PAGE>   7
                                  EXHIBIT INDEX


Exhibit Number   Description                      Page or Method of Filing
--------------   -----------                      ------------------------
5                Opinion of Snell & Wilmer                  8 
                 L.L.P.
23.1             Consent of Ernst & Young LLP,              9
                 Independent Auditors
23.2             Consent of Mauldin & Jenkins,              10
                 LLC
23.3             Consent of Snell & Wilmer         Included in Exhibit 5
                 L.L.P.


                                        7