UNITED STATES
                             SECURITIES AND EXCHANGE COMMISSION
                                   WASHINGTON, D.C. 20549



                                          FORM 10-K


  (Mark one)

  /X/ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
      EXCHANGE ACT OF 1934
      For the fiscal year ended December 31, 2004

      OR



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


      Commission File Number:  333-108551-07


        Asset Backed Funding Corporation
        Asset Backed Certificates
        Series 2004-OPT4

     (Exact name of registrant as specified in its charter)


   New York                                         54-2155107
  (State or other jurisdiction of                   54-2155108
  incorporation or organization)                    54-6621650
                                                    54-6621651
                                                    (I.R.S. Employer
                                                    Identification Nos.)


   c/o Wells Fargo Bank, N.A.
   9062 Old Annapolis Road
   Columbia, MD                                21045
  (Address of principal executive offices)     (Zip Code)


  Registrant's telephone number, including area code: (410) 884-2000


  Securities registered pursuant to Section 12(b) of the Act:

        NONE.


  Securities registered pursuant to Section 12(g) of the Act:

        NONE.


  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 ( 229.405 of this chapter) 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.

        Not applicable.


  Indicate by check mark whether the registrant is an accelerated filer
  (as defined in Exchange Act Rule 12b-2).

        Yes  ___     No  X


  State the aggregate market value of the voting and non-voting common
  equity held by non-affiliates computed by reference to the price at which
  the common equity was last sold, or the average bid and asked price of
  such common equity, as of the last business day of the registrant's most
  recently completed second fiscal quarter.

        Not applicable.


  Indicate the number of shares outstanding of each of the registrant's
  classes of common stock, as of the latest practicable date.

        Not applicable.


     Documents Incorporated by Reference

  List hereunder the following documents if incorporated by reference and
  the Part of the Form 10-K (e.g. Part I, Part II, etc.) into which the
  document is incorporated: (1)Any annual report to security holders; (2)
  Any proxy or information statement; and (3)Any prospectus filed pursuant
  to Rule 424(b) or (c) under the Securities Act of 1933. The listed
  documents should be clearly described for identification purposes (e.g.
  annual report to security holders for fiscal year ended December 24, 1980).

        Not applicable.




                          Introductory Note

  This Annual Report on Form 10-K is prepared in reliance on the no-action
  letter dated March 26, 1993 issued by the Securities and Exchange Commission
  to Nomura Asset Securities Corporation.


                                   PART I


  Item 1.  Business.

            Omitted.

  Item 2.  Properties.

            Not applicable.


  Item 3.  Legal Proceedings.

            The registrant knows of no material pending legal proceedings
            involving the trust created under the Pooling and Servicing
            Agreement (the Trust), the Trustee, the Master Servicer or the
            registrant with respect to the Trust other than routine
            litigation incidental to the duties of the respective parties.


  Item 4.  Submission of Matters to a Vote of Security Holders.

            None.


                                PART II

  Item 5.  Market for registrant's Common Equity, Related Stockholder
           Matters and Issuer Purchases of Equity Securities.

            No established public trading market for the Certificates exists.

            Records provided to the Trust by the DTC and the Trustee
            indicate that as of December 31, 2004, the total number of holders
            of record for the Series of Certificates is 25.


  Item 6.  Selected Financial Data.

            Omitted.


  Item 7.  Management's Discussion and Analysis of Financial Condition and
           Results of Operation.

            Omitted.


  Item 7A. Quantitative and Qualitative Disclosures about Market Risk.

            Not applicable.


  Item 8.  Financial Statements and Supplementary Data.

            Omitted.


  Item 9.  Changes in and Disagreements with Accountants on Accounting and
           Financial Disclosure.

            None.


  Item 9A. Controls and Procedures.

            Not applicable.


  Item 9B. Other Information.

            None.


                                PART III

  Item 10. Directors and Executive Officers of the Registrant.

            Not applicable.


  Item 11. Executive Compensation.

            Not applicable.


  Item 12. Security Ownership of Certain Beneficial Owners and Management.

            Not applicable.

  Item 13. Certain Relationships and Related Transactions.

            Not applicable.


  Item 14. Principal Accounting Fees and Services.

            Not applicable.


                                PART IV

  Item 15. Exhibits, Financial Statement Schedules.

   (a) The following is a list of documents filed as part of this Annual
          Report on Form 10-K:

     (4.1) Pooling and Servicing Agreement (filed as an exhibit to Form
           8-K on August 23, 2004).

     (31.1) Rule 13a-14(a)/15d-14(a) Certification.

     (99.1) Annual Independent Accountants' Servicing Reports concerning
            servicing activities for the year ended December 31, 2004.

     (99.2) Annual Statements of Compliance under the Pooling and Servicing
            Agreement for the year ended December 31, 2004.

     (99.3) Schedule of Year-To-Date Principal and Interest Distributions to
            Certificateholders.

    (b) The exhibits required to be filed by Registrant pursuant to Item 601
     of Regulation S-K are listed above and in the Exhibit Index that
     immediately follows the signature page hereof.

    (c) Not Applicable.

                                SIGNATURES

  Pursuant to the requirements of Section 13 or 15(d) of the Securities
  Exchange Act of 1934, the registrant has duly caused this report to be
  signed on its behalf by the undersigned, thereunto duly authorized:



    ABFC Asset-Backed Certificates
    Series 2004-OPT4
    (Registrant)


  Signed: Asset Backed Funding Corporation, as Depositor

  By:     Daniel B. Goodwin, President

  By: /s/ Daniel B. Goodwin, President

  Dated: March 28, 2005


  SUPPLEMENTAL INFORMATION TO BE FURNISHED WITH REPORTS FILED PURSUANT TO
  SECTION 15(d) OF THE ACT BY REGISTRANTS WHICH HAVE NOT REGISTERED
  SECURITIES PURSUANT TO SECTION 12 OF THE ACT.


  (a)(i) No annual report is provided to the Certificateholders other than
  with respect to aggregate principal and interest distributions.


  (a)(ii) No proxy statement, form of proxy or other proxy soliciting
  material has been sent to any Certificateholder with respect to any
  annual or other meeting of Certificateholders.



  Exhibit Index

  Exhibit No.


     (4.1) Pooling and Servicing Agreement (filed as an exhibit to Form
           8-K on August 23, 2004).

     (31.1) Rule 13a-14(a)/15d-14(a) Certification

     (99.1) Annual Independent Accountants' Servicing Reports concerning
            servicing activities for the year ended December 31, 2004.

     (99.2) Annual Statements of Compliance under the Pooling and Servicing
            Agreement for the year ended December 31, 2004.

     (99.3) Schedule of Year-To-Date Principal and Interest Distributions to
            Certificateholders.

                                                                    Exhibit 31.1

                                  Certification

I, Daniel B. Goodwin, the President of Asset Backed Funding Corporation, certify
that:

1.    I have reviewed this annual report on Form 10-K, and all monthly current
      reports on Form 8-K containing distribution or servicing reports filed in
      respect of periods included in the year covered by this annual report of
      the ABFC 2004-OPT4 Trust (the "Trust") formed pursuant to the Pooling and
      Servicing Agreement, dated as of June 1, 2004, among Asset Backed Funding
      Corporation, Option One Mortgage Corporation and Wells Fargo Bank, N.A.
      (the "Agreement");

2.    Based on my knowledge, the information in these reports, taken as a whole,
      does not contain any untrue statement of a material fact or omit to state
      a material fact necessary to make the statements made, in light of the
      circumstances under which such statements were made, not misleading as of
      the last day of the period covered by this annual report;

3.    Based on my knowledge, the distribution or servicing information required
      to be provided to the trustee by the master servicer under the Agreement
      for inclusion in these reports is included in these reports;

4.    Based on my knowledge and upon the annual compliance statement included in
      the report and required to be delivered to the trustee in accordance with
      the Agreement, and except as disclosed in the reports, the master servicer
      has fulfilled its obligations under the Agreement; and

5.    The reports disclose all significant deficiencies relating to the
      master servicer's compliance with the minimum servicing standards, based
      upon the report provided by an independent public accountant after
      conducting a review in compliance with the Uniform Single Attestation
      Program for Mortgage Bankers or similar procedure as set forth in the
      Agreement that is included in these reports.

In giving the certifications above, I have reasonably relied on information
provided to me by the following unaffiliated parties: Option One Mortgage
Corporation and Wells Fargo Bank, N.A.


                                          By: /s/ Daniel B. Goodwin
                                          Name:  Daniel B. Goodwin
                                          Title: President
                                          Dated: March 28, 2005


<PAGE>

  EX-99.1

(logo) KPMG

KPMG LLP
Suite 2000
355 South Grand Avenue
Los Angeles, CA 90071-1568


Independent Accountants' Report


The Board of Directors and Stockholder

Option One Mortgage Corporation


We have examined management's assertion, included in the accompanying
management assertion, that Option One Mortgage Corporation complied with the
minimum servicing standards set forth in the Mortgage Bankers Association of
America's Uniform Single Attestation Program for Mortgage Bankers as of and for
the year ended December 31, 2004. Management is responsible for Option One
Mortgage Corporation's compliance with those minimum servicing standards. Our
responsibility is to express an opinion on management's assertion about the
Company's compliance based on our examination.

Our examination was conducted in accordance with attestation standards
established by the American Institute of Certified Public Accountants and,
accordingly, included examining, on a test basis, evidence about Option One
Mortgage Corporation's compliance with the minimum servicing standards specified
above and performing such other procedures as we considered necessary in the
circumstances. We believe that our examination provides a reasonable basis for
our opinion. Our examination does not provide a legal determination on Option
One Mortgage Corporation's compliance with the minimum servicing standards.

In our opinion, management's assertion that Option One Mortgage Corporation
complied with the aforementioned minimum servicing standards as of and for the
year ended December 31, 2004 is fairly stated, in all material respects.

/s/ KMPG LLP


Los Angeles, California
February 28, 2005



KPMG LLP, a U.S. limited liability partnership, is the U.S.
member firm of KPMG international a Swiss cooperative.


<PAGE>


(logo) OPTION ONE
       MORTGAGE

(logo) H&R BLOCK
an H&R Block company


Management Assertion


As of and for the year ended December 31, 2004, Option One Mortgage Corporation
complied in all material respects with the minimum servicing standards set forth
in the Mortgage Bankers Association of America's Uniform Single Attestation
Program for Mortgage Bankers. As of and for this same period, Option One
Mortgage Corporation had in effect a fidelity bond and errors and omissions
policy in the amounts of $30,000,000 and $10,000,000, respectively.



/s/ Robert E. Dubrish
Robert E. Dubrish, Chief Executive Officer


/s/ William L. O'Neill
William L. O'Neill, Chief Financial Officer


/s/ Matthew A. Engel
Matthew A. Engel, Controller


/s/ John A. Vella
John A. Vella, Chief Servicing Officer






 EX-99.2

(logo)OPTION ONE MORTGAGE CORPORATION
an H&R Block company

(logo) H&R Block

February 28, 2005
Wells Fargo Bank, NA
9062 Old Annapolis Road MAC-N2702-011
Columbia, MD 21045-1951
Attn: Corporate Trust Services ABFC 2004-OPT4

Asset Backed Funding Corporation
214 North Tryon Street, 21st Floor
Charlotte, NC 28255
Attn: ABFC Asset-Backed Certificates, Series 2004-OPT4

Fitch, Inc.
One State Street Plaza
New York, NY 10004

Moody's Investors Service, Inc.
99 Church Street
New York, NY 10007

Standard & Poor's Rating Services
55 Water Street
New York, NY 10041

Re: ABFC 2004-OPT4 Trust

Pursuant to Section 3.19 of the Pooling and Servicing Agreement, dated and
effective as of June 1, 2004, among Asset Backed Funding Corporation as
Depositor, Option One Mortgage Corporation, as Master Servicer, and Wells Fargo
Bank, N.A., as Trustee, (the "Servicing Agreement"), enclosed is the required
officer's certificate of compliance.

If you have any questions, please contact Elizabeth Nguyen at (949) 790-3923

Option One Mortgage Corporation
3 Ada
Irvine, CA 92618


6501 IRVINE CENTER DRIVE * IRVINE * CA 92618 * 949-790-3600 * FAX 949-790-8570

OFFICER'S CERTIFICATE

ANNUAL STATEMENT OF THE SERVICER


I, William L. O'Neill, a duly appointed Senior Vice President/Chief
Financial Officer of Option One Mortgage Corporation, the Servicer, hereby
certify that (i) a review of the activities of the Servicer during the calendar
year ended December 31, 2004 and of performance under the Servicing Agreement,
as defined in the cover letter, has been made under my supervision, and (ii) to
the best of my knowledge, based on such review, the Servicer has fulfilled all
of its obligations under the Servicing Agreement during such year.


By: /s/ William L. O'Neill

Name: William L. O'Neill
Title: Senior Vice President/Chief Financial Officer
Date: February 28, 2005








  EX-99.3
   <TABLE>

   Class                              Interest             Principal               Losses             Ending Balance
   
                       <c>                    <c>                  <c>                 <c>
   A-1                            5,609,018.74         83,729,100.70                 0.00             494,873,899.30
   A-2                              955,732.51         13,963,750.33                 0.00              84,462,249.67
   CE                            14,542,548.42                  0.00                 0.00               3,936,776.66
   M-1                              501,243.62                  0.00                 0.00              42,905,000.00
   M-2                              441,985.20                  0.00                 0.00              30,309,000.00
   M-3                               81,527.31                  0.00                 0.00               5,117,000.00
   M-4                              139,197.74                  0.00                 0.00               7,872,000.00
   M-5                              102,960.04                  0.00                 0.00               5,511,000.00
   M-6                              206,109.73                  0.00                 0.00               7,872,000.00
   M-7                              175,214.23                  0.00                 0.00               6,692,000.00
   R1                                     0.00                  0.00                 0.00                       0.00
   R2                                     0.00                  0.00                 0.00                       0.00
   </TABLE>