<PAGE>
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549
                            ------------------------


                                  FORM 10-K/A


  /X/    ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
         SECURITIES EXCHANGE ACT OF 1934

                  FOR THE FISCAL YEAR ENDED DECEMBER 28, 1997
                                       OR

  / /    TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
         SECURITIES EXCHANGE ACT OF 1934

                FOR THE TRANSITION PERIOD FROM       TO       .

                        COMMISSION FILE NUMBER: 0-26126

                            SEROLOGICALS CORPORATION

             (Exact Name of Registrant as Specified in its Charter)

                  DELAWARE                             58-2142225
      (State or other jurisdiction of               (I.R.S. Employer
       incorporation or organization)            Identification Number)

       780 PARK NORTH BLVD., STE. 110                     30021
             CLARKSTON, GEORGIA                        (Zip Code)
           (Address of principal
             executive offices)

                                 (404) 296-5595
               (Registrant Telephone Number Including Area Code)

        SECURITIES REGISTERED PURSUANT TO SECTION 12(B) OF THE ACT: NONE

          SECURITIES REGISTERED PURSUANT TO SECTION 12(G) OF THE ACT:

                              TITLE OF EACH CLASS

                          Common Stock, $.01 par value

    Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past (90) days. Yes /X/  No / /

    Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K / /

    The aggregate market value of the shares of common stock held by
non-affiliates (based upon the closing sale price on The Nasdaq Stock Market) on
March 20, 1998 was approximately $427,315,000. As of March 20, 1998, there were
15,727,035 shares of Common Stock, $0.01 par value per share, outstanding.

                      DOCUMENTS INCORPORATED BY REFERENCE.

    Portions of the definitive proxy statement for the Annual Meeting of
Stockholders (which will be filed pursuant to Regulation 14A within 120 days of
the close of the Registrant's fiscal year ended December 28, 1997) shall be
deemed to be incorporated by reference in Part III.
<PAGE>

    This 10-K/A is being filed to amend the Financial Data Schedules. All other
information included in the initial filing is correct.

<PAGE>

                                   SIGNATURES



    Pursuant to the requirements of the Securities Exchange Act of 1934,
Serologicals Corporation has duly caused this Amendment on Form 10-K/A to be
signed on its behalf by the undersigned, thereunto duly authorized on March 30,
1998.



<TABLE>
<S>                             <C>  <C>
                                SEROLOGICALS CORPORATION
                                (REGISTRANT)

                                By:             /s/ RUSSELL H. PLUMB
                                     -----------------------------------------
                                                  Russell H. Plumb
                                     VICE PRESIDENT AND CHIEF FINANCIAL OFFICER
</TABLE>


                                      II-1
<PAGE>

                                 EXHIBIT INDEX


<TABLE>
<C>        <S>
      3.1  Amended and Restated Certificate of Incorporation (Exhibit 3.1 to the Registrant's
           Registration Quarterly Report on Form 10-Q for the period ended June 29, 1997, is
           hereby incorporated by reference).
      3.2  Amended and Restated By-laws (Exhibit 3.4 to the Registrant's Registration Statement
           on Form S-1 (File No. 33-91176), effective June 14, 1995, is hereby incorporated by
           reference).
      4.1  Specimen Common Stock Certificate (Exhibit 4.1 to the Registrant's Registration
           Statement on Form S-1 (File No. 33-91176), effective June 14, 1995, is hereby
           incorporated by reference).
      4.2  Amended and Restated Shareholders Agreement, dated as of August 31, 1993, as amended
           (Exhibit 4.2 to the Registrant's Registration Statement on Form S-1 (File No.
           33-91176), effective June 14, 1995, is hereby incorporated by reference).
    4.2.1  Amendment No. 3 to Amended and Restated Shareholders Agreement (Exhibit 4.2.1 to the
           Registrant's Registration Statement on Form S-1 (File No. 33-91176), effective June
           14, 1995, is hereby incorporated by reference).
    4.2.2  Amendment No. 4 to Amended and Restated Shareholders Agreement (Exhibit 4.2.2 to the
           Registrant's Annual Report on Form 10-K for the period ended December 31, 1995 is
           hereby incorporated by reference).
   10.1.1  Second Amended and Restated Credit Agreement, dated as of October 16, 1997, between
           the Company and NationsBank NA.*
   10.1.2  Revolving Note, dated October 16, 1997, from the Company in favor of NationsBank
           NA.*
     10.2  Convertible Subordinated Promissory Note, dated December 23, 1994, from the Company
           in favor of Gagnard & Marceaux Flint, Inc. (Exhibit 10.8 to the Registrant's
           Registration Statement on Form S-1 (File No. 33-91176), effective June 14, 1995, is
           hereby incorporated by reference).
   10.2.1  Agreement to Amend Convertible Subordinated Promissory Note and Amended and Restated
           Convertible Subordinated Promissory Note from the Company in favor of Gagnard and
           Marceaux Flint, Inc., dated January 18, 1996. (Exhibit 10.5.1 to the Registrant's
           Annual Report on Form 10-K for the period ended December 31, 1995 is hereby
           incorporated by reference).
   10.2.2  Agreement to Amend Convertible Subordinated Promissory Note and Amended and Restated
           Convertible Subordinated Promissory Note from the Company in favor of Gagnard and
           Marceaux Flint, Inc., dated January 24, 1997 (Exhibit 10.3.2 to the Registrants
           Annual Report on Form 10-K for the period ended December 31, 1995 is hereby
           incorporated by reference).
     10.3  Warrant of the Company dated March 9, 1993 issued to State Street Bank & Trust
           Company (Exhibit 10.10 to the Registrant's Registration Statement on Form S-1 (File
           No. 33-91176), effective June 14, 1995, is hereby incorporated by reference).
   10.3.1  Amendment to Warrant of the Company issued to State Street Bank & Trust Company
           (Exhibit 10.10.1 to the Registrant's Registration Statement on Form S-1 (File No.
           33-91176), effective June 14, 1995, is hereby incorporated by reference).
   10.3.2  Amendment to Warrant of the Company issued to State Street Bank & Trust Company
           (Exhibit 10.10.2 to the Registrant's Registration Statement on Form S-1 (File No.
           33-91176), effective June 14, 1995, is hereby incorporated by reference).
     10.4  Plasma Purchase Agreement, dated as of December 20, 1994, between Seramune, Inc.
           (now known as Seramed, Inc.) and Bayer, Inc. (Exhibit 10.11 to the Registrant's
           Registration Statement on Form S-1 (File No. 33-91176), effective June 14, 1995, is
           hereby incorporated by reference).
     10.5  Technical Collaboration Agreement, dated February 10, 1995, between Bioscot Limited
           and The Common Services Agency (Exhibit 10.12 to the Registrant's Registration
           Statement on Form S-1 (File No. 33-91176), effective June 14, 1995, is hereby
           incorporated by reference).
   10.5.1  IP Acquisition Agreement, dated February 10, 1995, between Bioscot Limited and The
           Common Services Agency (Exhibit 10.12.1 to the Registrant's Registration Statement
           on Form S-1 (File No. 33-91176), effective June 14, 1995, is hereby incorporated by
           reference).
     10.6  Employment Agreement, dated as of March 8, 1993, between Serologicals, Inc. and
           Harold J. Tenoso, as amended (Exhibit 10.13 to the Registrant's Registration
           Statement on Form S-1 (File No. 33-91176), effective June 14, 1995, is hereby
           incorporated by reference).+
</TABLE>
<PAGE>

<TABLE>
<C>        <S>
     10.7  1994 Amended and Restated Omnibus Incentive Plan (Exhibit 10.11.1 to the
           Registrant's Annual Report on Form 10-K for the period ended December 31, 1995, is
           hereby incorporated by reference).+
     10.8  Forms of Stock Option Agreement (Exhibit 10.15 to the Registrant's Registration
           Statement on Form S-1 (File No. 33-91176), effective June 14, 1995, is hereby
           incorporated by reference).+
   10.8.1  Forms of First Revised Stock Option Agreements (Exhibit 10.12.1 to the Registrant's
           Annual Report on Form 10-K for the period ended December 31, 1995, is hereby
           incorporated by reference).+
   10.8.2  Forms of Second Revised Stock Option Agreements (Exhibit 10.10.2 to the Registrant's
           Annual Report on Form 10-K for the period ended December 29, 1996, is hereby
           incorporated by reference).+
     10.9  1995 Non-Employee Directors' Stock Option Plan, as amended (Exhibit 10.13 to the
           Registrant's Annual Report on Form 10-K for the period ended December 31, 1995, is
           hereby incorporated herein by reference).+
    10.10  Form of Indemnification Agreement (Exhibit 10.16 to the Registrant's Registration
           Statement on Form S-1 (File No. 33-91176), effective June 14, 1995, is hereby
           incorporated by reference).
    10.11  1996 Employee Stock Purchase Plan (Exhibit 10.18 to the Registrant's Annual Report
           on Form 10-K for the period ended December 31, 1995, is hereby incorporated by
           reference).+
    10.12  Employment Agreement between the Company and Charles P. Harrison (Exhibit 10.19 to
           the Registrant's Annual Report on Form 10-K for the period ended December 31, 1995,
           is hereby incorporated by reference).+
    10.13  Stock and Asset Purchase Agreement, dated March 6, 1996, among Seramune, Inc. and
           Concho Biologics, Inc., a Delaware corporation and Southeastern Biologics, Inc.,
           Plasma Management, Inc., Concho Biologics, Inc., a Texas corporation, Daryl Burke,
           Richard Devoll and Adrian P. Scallan (Exhibit 2.1 to the Company's current report on
           Form 8-K, dated March 20, 1996, is hereby incorporated by reference).
    10.14  Purchase Agreement, dated March 6, 1997, among Serologicals Corporation, Seramune,
           Inc., Seronat Plasma, Inc., Nations Biologics, Inc., Decatur Plasma, Inc.,
           Bloomington Plasma, Inc., Lake Forest Plasma Center, Inc., Southwest Plasma Company,
           Inc., Riverfront Plasma Company, Inc., Green Street Biological Corp., Silver State
           Plasma Products, Inc., Rodney L. Savoy, Barry J. Heinen, Noel P. Dragon, Jr. and La
           Savoy Famille, L.C. (Exhibit 2.1 to the Company's Current Report on Form 8-K, dated
           March 21, 1997, is hereby incorporated by reference).
    10.15  Promissory Note, dated March 6, 1997 from the Company in favor of Rodney L. Savoy
           (Exhibit 99 to the Company's Current Report on form 8-K, dated March 21, 1997, is
           hereby incorporated by reference).
    10.16  Employment Agreement between the Company and Terence Dobson (Exhibit 10.1 to the
           Company's Quarterly Report on Form 10-Q for the quarter ended September 29, 1996, is
           hereby incorporated by reference).+
    10.17  Serologicals Corporation 1996 UK Sharesave Scheme (Exhibit 10.9 to the Registrant's
           Annual Report on Form 10-K for the period ended December 29, 1996, is hereby
           incorporated by reference).+
    10.18  Employment Agreement between the Company and P. Anne Hoppe (Exhibit 10.1 to the
           Company's Quarterly Report on Form 10Q for the quarter ended June 29, 1997, is
           hereby incorporated by reference).+
    10.19  Employment Agreement between the Company and Toby L. Simon, M.D. (Exhibit 10.2 to
           the Company's Quarterly Report on Form 10Q for the quarter ended June 29, 1997, is
           hereby incorporated by reference).+
       21  Subsidiaries of the Company.*
     23.1  Consent of Arthur Andersen LLP.*
       27  Restated Financial Data Schedule for the fiscal quarters ended March 30, 1997, June
           29, 1997 and September 28, 1997.*
     27.1  Financial Data Schedule for the fiscal year ended December 28, 1997.*
</TABLE>

<PAGE>

<TABLE>
<C>        <S>
     27.2  Restated Financial Data Schedule for the fiscal years ended December 31, 1995 and
           December 29, 1996 and the fiscal quarters ended March 31, 1996, June 30, 1996 and
           September 29, 1996*.
</TABLE>


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

*   Filed herewith

+  Compensatory Plan or Arrangement