UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549


                                    FORM 10-K

[X]      Annual  report  pursuant  to  Section  13 or  15(d)  of the Securities
         Exchange   Act  of  1934  for the  fiscal year ended December 31, 2003

[  ]     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 333-100669-14

               CREDIT SUISSE FIRST BOSTON MORTGAGE SECURITIES CORP.
             (Exact name of registrant as specified in its charter)

         Delaware                                            13-3320910
(State or other jurisdiction of                           I.R.S. Employer
incorporation or organization)                            Identification No.)

11 Madison Ave.
New York, New York                                             10010
(Address of Principal Executive Offices)                      (Zip Code)

       Registrant's telephone number, including area code :(212)325-2000


         CREDIT SUISSE FIRST BOSTON MORTGAGE SECURITIES CORP.
    CSFB MORTGAGE-BACKED PASS-THROUGH CERTIFICATES, SERIES 2003-AR12
       (Title of each class of securities covered by this Form)

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 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. [X]

Indicate by check mark whether the registrant is an accelerated filer (as
defined in Exchange Act Rule 12b-2). Yes  No [X]


Documents incorporated by reference:  None



<PAGE>

CREDIT SUISSE FIRST BOSTON MORTGAGE SECURITIES CORP.
CSFB MORTGAGE-BACKED PASS-THROUGH CERTIFICATES, SERIES 2003-AR12
----------------------------------------------------------------

PART I

Item 1.  Business

         Omitted.

Item 2.  Properties

         Omitted.

Item 3.  Legal Proceedings

The  Registrant is not aware of any material legal  proceeding  with respect to,
the Company, the Master Servicer, the Servicers,  the Trust Administrator or the
Trustee, in each case if applicable, as related to the Trust.

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

No  matter  was  submitted  to a vote  or  consent  of  Holders  of the  Offered
Certificates during the fiscal year covered by this report.


PART II

Item 5.  Market for Registrant's Common Equity and Related Stockholder Matters

The Trust does not issue stock. There is currently no established secondary
market for the Certificates.  As of  December  31,  2003,  the number
of holders  of each  Class  of  Offered  Certificates was 27.


Item 6.  Selected Financial Data

         Omitted.

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

         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

There was no change of  accountants  or  disagreement  with  accountants  on any
matter of accounting principles or practices or financial disclosure.

Item 9a. Controls and Procedures

         Not Applicable

                                      -2-

<PAGE>

PART III

Item 10. Directors and Executive Officers of the Registrant

         Omitted.

Item 11. Executive Compensation

         Omitted.

Item 12. Security Ownership of Certain Beneficial Owners and Management

         Omitted.


Item 13. Certain Relationships and Related Transactions

        No reportable transactions have occurred.

Item 14. Principal Accounting Fees and Services

         Not applicable.

PART IV

Item 15. Exhibits, Financial Statement Schedules and Reports on Form 8-K

(a) The following documents are filed as part of this report:

    (1) Financial Statements:
         Omitted.

    (2)  Financial Statement Schedules:
         Omitted.

    (3)  Exhibits:

   Annual Independent Accountants' Servicing Report,
   filed as Exhibit 99.1 hereto.

   Annual Servicer's  Statement of  Compliance,  filed as Exhibit 99.2, hereto.

(b)   Reports on Form 8-K: The  following  Current  Reports on Form 8-K were
      filed by the Registrant during the last quarter of 2003.

      Current  Reports   on Form 8-K,   dated   October 27,  2003,  November 25,
     2003,  and  December  26,  2003,  were filed for the  purpose of filing the
     Monthly  Statement  sent to the  Holders of the  Offered  Certificates  for
     payments made on the same dates.  The items reported in such Current Report
     were Item 5 and Item 7.

(c)   Exhibits to this report are listed in Item (15)(a)(3) above.

(d) Not applicable.



                                      -3-
<PAGE>
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.

Credit Suisse First Boston Mortgage Securities Corp.
CSFB Mortgage-Backed Pass-Through Certificates, Series 2003-AR12

By:     /s/  Andrew Kiumura
        ------------------------------
Name:         Andrew Kimura

Title:        President

Company:      Credit Suisse First Boston Mortgage Securities Corp.

Date:         March 29, 2004



                                      -4-
<PAGE>
Sarbanes-Oxley Certification

I, Andrew Kimura, certify that:

1.   I have reviewed  this annual  report on Form 10-K,  and all 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 Credit
     Suisse  First  Boston  Mortgage  Securities  Corp.,  CSFB   Mortgage-Backed
     Pass-Through Certificates, Series 2003-AR12

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  servicer  under the  pooling  and
     servicing,  or  similar,  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 terms of the pooling and servicing agreement, or similar agreement, and
     except  as  disclosed  in the  reports,  the  servicer  has  fulfilled  its
     obligations under the servicing agreement; and

5.   The  reports  disclose  all  significant   deficiencies   relating  to  the
     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  pooling  and
     servicing or similar 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:   the  Trustee,  each
Servicer and the Master Servicer.

Date:             March 29, 2004

Signature:       /s/  Andrew Kiumura
                ------------------------------
Company:          Credit Suisse First Boston Mortgage Securities Corp.

Title:            President

                                      -5-

<PAGE>


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.

The  registrant  has not sent an annual report or proxy material to its security
holders.  The registrant  will not be sending an annual report or proxy material
to its security holders subsequent to the filing of this form.

                                      -6-
<PAGE>


                                 EXHIBIT INDEX

Exhibit     Description

99.1    Annual Independent Accountant's Servicing Report

        a) Chase Manhattan Mortgage Corporation, as Master Servicer
        b) Washington Mutual Mortgage Securities Corp., as Servicer
        c) Cendant Mortgage Corporation, as Servicer
        d) Fairbanks Capital Corp., as Servicer
        e) Ocwen Federal Bank FSB, as Servicer

99.2    Annual Servicer's Statement of Compliance

        a) Chase Manhattan Mortgage Corporation, as Master Servicer
        b) Washington Mutual Mortgage Securities Corp., as Servicer
        c) Cendant Mortgage Corporation, as Servicer
        d) Fairbanks Capital Corp., as Servicer
        e) Ocwen Federal Bank FSB, as Servicer



                                      -7-



<PAGE>


EXHIBIT 99.1 - Annual Independent Accountant's Servicing Report


Chase Manhattan Mortgage Corporation, as Master Servicer
------------------------------------------------------------



PricewaterhouseCoopers, LLP
1177 Avenue of the Americas
New York, NY  10026
Telephone:  (646)  471-4000
Facsimile:  (646)  471-4100


                       REPORT OF INDEPENDENT AUDITORS


To the Board of Directors of
Chase Manhattan Mortgage Corporation


     We have examined  management's  assertion  about Chase  Manhattan  Mortgage
Corporation's (the "Company") compliance with the minimum servicing standards as
set forth in the  Mortgage  Bankers  Association  of  America's  Uniform  Single
Attestation  Program for Mortgage  Bankers ("USAP") as of and for the year ended
December 31, 2003. The Company has  interpreted  USAP and  determined  that USAP
minimum  servicing  standards I.1, I.2, I.3, III.1,  III.5,  IV.1, and VII.1 are
applicable to master servicers and are included in the  accompanying  management
assertion (see Exhibit I). The Company has interpreted  USAP and determined that
USAP minimum  servicing  standards I.4, II.1, II.2, II.3,  II.4,  III.2,  III.3,
III.4,  III.6,  V.1,  V.2,  V.3,  V.4 and  VI.1  are not  applicable  to  master
servicers.  In cases where the Company does not service the loans underlying the
master servicing,  our procedures were limited to testing  management policy, of
obtaining and reviewing USAP reports from the subservicers' independent auditors
on an annual basis,  and obtaining an reading the most recently  available  USAP
reports  from  the  subservicers'  independent  auditors.  In this  regards,  we
obtained  USAP  reports  for the  year  ended  December  31,  2003 on 16% of the
subservicers.  These  subservicrs  serviced  loans  comprising 75% of the unpaid
principal balance of the Company's Master Servicing portfolio as of December 31,
2003.

     Our opinion as expressed  herein,  as it relates to USAP minimum  servicing
standards for which subservicers are responsible for compliance, is based solely
upon the  reports  of the  subservicers'  independent  auditors.  Management  is
responsible for the Company's  compliance with the remaining  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 made in accordance with attestion standards established
by the American  Institute of Certified  Public  Accountants  and,  accordingly,
included  examining,  on a test basis,  evidence about the Company's  compliance
with the minimum  servicing  standards and performing such other such procedures
as we considered necessary in the circumstances. We believe that our examination
and the  reports  of the  other  auditors  provide  a  reasonable  basis for our
opinion. Our examination does not provide a legal determination on the Company's
compliance with the minimum servicing standards.

     In  our  opinion,   based  on  our  examination  and  the  reports  of  the
subservicer's  independent  auditors,  management's  assertion  that the Company
complied with the aforementioned  minimum servicing  standards as of and for the
year ended December 31, 2003 is fairly stated, in all material respects.


By:  /s/ PricewaterhouseCoopers, LLC
------------------------------------
PricewaterhouseCoopers, LLC


March 15,  2004

<page>

                                                                       EXHIBIT I

Chase Manhattan Mortgage Corporation
3415 Vision Drive
Columbus, OH  43219-6009


             MANAGEMENT'S ASSERTION CONCERNING COMPLIANCE WITH USAP
                          MINIMUM SERVICING STANDARDS

March 15, 2004

     As of and for the year ended December 31, 2003,  Chase  Manhattan  Mortgage
Corporation  (the  "Company"),  has 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 ("USAP") that
we have determined are applicable to master servicers.  We have interpreted USAP
and determined that minimum  servicing  standards I.1, I.2, I.3,  III.1,  III.5,
IV.1, and VII.1 as set forth in USAP are applicable to master servicers. We have
also  interpreted that USAP minimum  servicing  standards I.4, II.1, II.2, II.3,
II.4, III.2,  III.3,  III.4,  III.6, V.1, V.2, V.3, V.4 and VI.1 as set forth in
USAP  are not  applicable  to  master  servicers;  for  thse  minimum  servicing
standards  the  Company  relies  on the  performance  of its  subservicers.  The
assertion relates specifically to the Company's Master Servicing Portfolio.

     It is the policy of the Company to obtain USAP reports from the independent
auditors of its  subservicers on an annual basis.  Not all of those USAP reports
for the year ended  December  31, 2003 will be  available as of the date of this
report.  As of March 15, 2004,  the Company has obtained USAP reports for 16% of
its subservicers. These subservicers serviced loans comprising 75% of the unpaid
principal balance of the Company's Master Servicing Portfolio as of December 31,
2003.  Any  items  of  non-compliance  noted  in  the  USAP  received  from  the
subservicers  as of the date of this  report,  have been  included in Exhibit II
hereto.

     As of and for this same period, the Company had in effect fidelity bond and
errors and ommissions  policy in the amounts of  $250,000,000  and  $25,000,000,
respectively.


By:  /s/ Bonnie Collins
-----------------------------
Bonnie Collins
Senior Vice President
Chase Manhattan Mortgage Corporation

By: /s/  Diane Bentz
-----------------------------
Diane Bentz
Senior Vice President
Chase Manhattan Mortgage Corporation


<page>

                                                                Exhibit II

                      Chase Manhattan Mortgage Corporation
                      Subservicers' USAP Report Exceptions
                               December 31, 2003


     It is the policy of Chase Manhattan Mortgage Corporation (the "Company") to
obtain Uniform Single Attestation  Program for Mortgage Bankers ("USAP") reports
from the  independent  auditors of its  subservicers.  As of March 15, 2004, the
Company  has  obtained  USAP  reports  for  16%  of  its   subservicers.   These
subservicers  serviced loans comprising 75% of the unpaid  principal  balance of
the Company's  Master  Servicing  Portfolio as of December 31, 2003. The Company
noted that a number of the USAP reports  contained items of  noncompliance.  The
following summarizes the items from these reports.

Servicer                                        Exception

Ocwen Federal Bank FSB     .  Interest on escrow accounts in certain states
                              was not paid, or credited, to mortgagors in
                              accordance  with the  applicable state laws
                              during the year ended December 31, 2003.

                           .  Certain reconciling items which arose during
                              the year ended December 31, 2003 were not
                              specifically identified and/or were not
                              cleared within 90 days of their original
                              identification.

                                      -8-

<PAGE>
Washington Mutual Mortgage Securities Corp., as Servicer
----------------------------------------------------------


Deloitte & Touche LLP
Suite 3300
925 Fourth Avenue
Seattle, WA 98104-1126
USA
Tel: +1 206 716 7000
Fax: +1 206 965 7000
www.deloitte.com


INDEPENDENT ACCOUNTANTS' REPORT

Board of Directors
Washington Mutual, Inc. and Subsidiaries

     We have examined  management's  assertion that Washington Mutual,  Inc. and
subsidiaries  (the "Company") has complied as of and for the year ended December
31, 2003, with its  established  minimum  servicing  standards for single family
residential  mortgaged  identified in the accompanying  Management's  Assertion,
dated February 16, 2004.  Management is responsible for the Company'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 the Company's
compliance  with its  minimum  servicing  standards  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 the Company's  compliance with its minimum
servicing standands.

     In our opinion,  management's  assertion that the Company complied with the
aforementioned minimum servicing standards as of and for the year ended December
31, 2003 is fairly stated, in all material  respects,  based on the criteria set
forth in Appendix I.



By:  /s/ Deloitte & Touche LLP
---------------------------

February 16, 2004


                                                        WASHINGTON MUTUAL


MANAGEMENT'S ASSERTION

     As of and for the year ended December 31, 2003,  Washington Mutual Inc. and
Subsidiaries  (the Company) has  complied,  in all material  respects,  with the
Company's  established minimum servicing standards for single family residential
mortgages as set forth in Appendix I (the Standard).  The Standards are based on
the Mortgage  Banker's  Association  of  America's  Uniform  Single  Attestation
Program for Mortgage Bankers. As of and for this same period, the Company had in
effect a fidelity bond in the amount of $110  million,  and errors and omissions
policy in the amount of $20 million.



By:  /s/ Deanna Oppenheimer
-----------------------------
Deanna Oppenheimer
President
Consumer Group


By:  /s/ Dyan Beito
-----------------------------
Dyan Beito
Executive Vice President
Home Loans Service Delivery-Consumer Group


By:  /s/ Anthony T. Meola
-----------------------------
Anthony T. Meola
Executive Vice President
Home Loans Production-Consumer Group


February 16, 2004

                                                        WASHINGTON MUTUAL

WASHINGTON MUTUAL, INC. AND SUBSIDIARIES

APPENDIX I: MINIMUM SERVICING STANDARDS FOR SINGLE FAMILY RESIDENTIAL  MORTGAGES
AS SET FORTH IN THE MORTGAGE  BANKERS  ASSOCIATION  OF AMERICA'S  UNIFORM SINGLE
ATTESTATION PROGRAM FOR MORTGAGE BANKERS

I.   CUSTODIAL BANK ACCOUNTS

1.   Reconciliations shall be prepared on a monthly basis for all custodial bank
     accounts and related bank clearing accounts. These reconciliations shall:

      .  be mathematically accurate;

      .  be prepared within forty-five (45) calendar days after the cutoff date;

      .  be reviewed and approved by someone other than the person who prepared
         the reconciliation; and

      .  document explanations for reconciling items.  These reconciling items
         shall be resolved within ninety (90) calendar days of their original
         identification.

2.   Funds of the servicing  entity shall be advanced in cases where there is an
     overdraft in an investor's or a mortgagor's account.

3.   Each  custodial   account  shall  be  maintained  at  a  federally  insured
     depository institution in trust for the applicable investor.

4.   Escrow  funds  held in  trust  for a  mortgagor  shall be  returned  to the
     mortgagor within thirty (30) calendar days of payoff of the mortgage loan.

II.  MORTGAGE PAYMENTS

1.   Mortgage  payments  shall be deposited into the custodial bank accounts and
     related bank clearing accounts within two business days of receipt.

2.   Mortgage  payments made in accordance with the  mortgagor's  loan documents
     shall be posted to the  applicable  mortgagor  records  within two business
     days of receipt.

3.   Mortgage  payments  shall be allocated to principal,  interest,  insurance,
     taxes or  other  escrow  items in  accordance  with  the  mortgagor's  loan
     documents.

4.   Mortgage  payments  identified  as  loan  payoffs  shall  be  allocated  in
     accordance with the mortgagor's loan documents.

III. DISBURSEMENTS

1.   Disbursements  made via wire  transfer on behalf of a mortgagor or investor
     shall be made only by authorized personnel.

2.   Disbursements  made on behalf of a mortgagor  or  investor  shall be posted
     within  two  business  days  to  the  mortgagor's  or  investor's   records
     maintained by the servicing entity.

3.   Tax and  insurance  payments  shall be made on or  before  the  penalty  or
     insurance policy  expiration dates, as indicated on tax bills and insurance
     premium notices, respectively, provided that such support has been received
     by the  servicing  entity at least thirty (30) calendar days prior to these
     dates.

4.   Any late payment  penalties paid in conjunction with the payment of any tax
     bill or insurance premium notice shall be paid from the servicing  entity's
     funds and not charged to the mortgagor,  unless the late payment was due to
     the mortgagor's error or omission.

5.   Amounts  remitted to investors per the  servicer's  investor  reports shall
     agree with cancelled  checks,  or other form of payment,  or custodial bank
     statements.

6.   Unused checks shall be safeguarded so as to prevent unauthorized access.

IV.  INVESTOR ACCOUNTING AND REPORTING

1.   The servicing  entity's investor reports shall agree with, or reconcile to,
     investors'  records  on a monthly  basis as to the total  unpaid  principal
     balance and number of loans serviced by the servicing entity.

V.   MORTGAGOR LOAN ACCOUNTING

1.   The servicing entity's mortgage loan records shall agree with, or reconcile
     to, the records of mortgagors with respect to the unpaid principal  balance
     on a monthly basis.

2.   Adjustments  on ARM loans shall be computed  based on the related  mortgage
     note and any ARM rider.

3.   Escrow accounts shall be analyzed,  in accordance with the mortgagor's loan
     documents, on at least an annual basis.

4.   Interest on escrow  accounts  shall be paid, or credited,  to mortgagors in
     accordance with the applicable state laws.

VI.  DELINQUENCIES

1.   Records  documenting  collection  efforts  shall be  maintained  during the
     period a loan is in default  and shall be updated  at least  monthly.  Such
     records shall  describe the entity's  activities  in monitoring  delinquent
     loans  including,  for example,  phone calls,  letters and mortgage payment
     rescheduling  plans in cases  where the  delinquency  is  deemed  temporary
     (e.g., illness or unemployment).

VII. INSURANCE POLICIES

1.   A fidelity bond and errors and  omissions  policy shall be in effect on the
     servicing entity  throughout the reporting period in the amount of coverage
     represented to investors in management's assertion.


                                -9-

<PAGE>
Cendant Mortgage Corporation, as Servicer
-----------------------------------------


Deloitte & Touche LLP
750 College Road East
Third Floor
Princeton, New Jersey 08540
Tel (609) 514-3600
Fax ((609) 514-3603
www.deloitte.com


INDEPENDENT ACCOUNTANTS' REPORT


To Cendant Mortgage Corporation:

     We  have   examined   management's   assertion   about   Cendant   Mortgage
Corporation's  compliance with the minimum servicing standards identified in the
Mortgage Bankers Association of America's Uniform Single Attestation Program for
Mortgage  Bankers (USAP) as of and for the year ended December 31, 2003 included
in the accompanying management assertion.  Management is responsible for Cendant
Mortgage  Corporation's  compliance with those minimum servicing standards.  Our
responsibility  is to express an opinion  on  management's  assertion  about the
entity's compliance based on our examination.

     Our examination  was made in accordance  with standards  established by the
American  Institute of Certified Public Accountants and,  accordingly,  included
examining,  on a test  basis,  evidence  about  Cendant  Mortgage  Corporation's
compliance  with the  minimum  servicing  standards  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 Cendant Mortgage  Corporation's  compliance
with the minimum servicing standands.

     In our opinion,  management's  assertion that Cendant Mortgage  Corporation
complied with the aforementioned  minimum servicing  standards as of and for the
year ended December 31, 2003 is fairly stated, in all material respects.

     This report is intended  solely for the information and use of the Company,
investors in loans  serviced by the Company and their  independent  auditors for
their  evaluation  of  the  Company's   compliance  with  applicable   servicing
agreements,  and is not intended to be and should not be  distributed to or used
by anyone other than these specified parties.

By:  /s/ Deloitte & Touche LLP
---------------------------

February 23, 2004



Cendant Mortgage
300 Leadenhall Road
Mount Laurel, NJ  08054



     As  of  and  for  the  year  ended  December  31,  2003,  Cendant  Mortgage
Corporation (the Company) has 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,  the  Company  had in effect a fidelity  bond and errors and  ommissions
policy in the amounts of $120 million and $20 million, respectively.


Cendant Mortgage Corporation


By:   /s/ Terence W. Edwards
-----------------------------
Terence W. Edwards
President and Chief Executive Officer


By:   /s/ Mark Danahy
-----------------------------
Mark Danahy
Senior Vice President and Chief Financial Officer



By:  /s/ Martin L. Foster
-----------------------------
Martin L. Foster
Senior Vice President -- Loan Servicing


                                        -10-
<PAGE>
Fairbanks Capital Corp., as Servicer
-------------------------------------


Ernst  & Young LLP
725 South Figueroa Street
Los Angeles, CA  90017
Telephone:  (213) 977-4200
www.ey.com


                       Report on Management's Assertion on
          Compliance with Minimum Servicing Standards Set Forth in the
             Uniform Single Attestation Program for Mortgage Bankers

                       Report of Independent Accountants

Board of Directors
Fairbanks Capital Corp.

     We have  examined  management's  assertion,  included  in the  accompanying
report titled Report of Management, that Fairbanks Capital Corp., a wholly owned
subsidiary of Fairbanks Capital Holding Corp.,  ("Fairbanks")  complied with the
minimum  servicing  standards set forth in the Mortgage  Bankers  Association of
America's Uniform Single Attestation Program for Mortgage Bankers (USAP) for the
year ended  December 31, 2003.  Management  is  responsible  for the  Fairbanks'
compliance with those requirements.  Our responsibility is to express an opinion
on  management's  assertions  about  the  Fairbanks'  compliance  based  on  our
examination.

     Our examination  was conducted in accordance with standards  established by
the  American  Institute  of  Certified  Public  Accountants  and,  accordingly,
included examining,  on a test basis,  evidence about the Fairbanks'  compliance
with those  requirements  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 the Fairbanks' compliance with specified requirements.

     In our opinion,  management's  assertion,  that Fairbanks complied with the
aforementioned  requirements  for the year ended  December 31,  2003,  is fairly
stated, in all material respects.

     This report is inended solely for the  information  and use of the Board of
Directors, Audit Committee,  management, Fannie Mae, Freddie Mac, Ginnie Mae and
other  investors in serviced  assets and is not intended to be and should not be
used by anyone other than these specified parties.

By:  /s/ Ernst & Young LLP
--------------------------

January 19, 2004




FAIRBANKS CAPITAL CORP.
815 South West Temple
Salt Lake City, Utah  84115-4412
P.O. Box 65250
Salt Lake City, Utah  84165-0250
telephone (801) 293-1883
fax (801) 293-1297


                      Management's Assertion on Compliance
                 with the Minimum Servicing Standards set forth
         in the Uniform Single Attestation Program for Mortgage Bankers

                              Report of Management

     We, as members of management of Fairbanks Capital Corp.  ("Fairbanks),  are
responsible for complying with the minimum  servicing  standards as set forth in
the Mortgage Bankers Association of America's Uniform Single Attestation Program
for Mortgage  Bankers  ("USAP").  We are also  responsible for  establishing and
maintaining effective internal control over compliance with these standards.  We
have  performed an  evaluation  of the  Fairbanks'  compliance  with the minimum
servicing standards as set forth in the USAP as of December 31, 2003 and for the
year then ended. Based on this evaluation,  we assert that during the year ended
December 31, 2003, the Fairbanks  complied,  in all material respects,  with the
minimum servicing standards set forth in the USAP.

     As of  December  31,  2003 and for the year then  ended,  Fairbanks  had in
effect a fidelity bond in the amount of $55,000,000  and an errors and omissions
policy in the amount of $20,000,000.

/s/  James H. Ozanne
--------------------------
James H. Ozanne
Chief Executive Officer

/s/ Matthew L. Hollingsworth
---------------------------
Matthew L. Hollingsworth
Chief Operating Officer

/s/ Barbara K. Wing
---------------------------
Barbara K. Wing
Senior Vice President and Controller

January 19, 2004




                                       -10-
<PAGE>
 Ocwen Federal Bank FSB, as Servicer
---------------------------------------

PricewaterhouseCoopers LLP
222 Lakeview Avenue
Suite 360
West Palm Beach, FL 33401


INDEPENDENT CERTIFIED PUBLIC ACCOUNTANT'S REPORT

To the Board of Directors
Ocwen Federal Bank FSB

     We have  examined  management's  assertion,  included  in the  accompanying
Management Assertion of Conpliance with USAP, that, except for the noncompliance
related  reconciliations  described in the third paragraph and the noncompliance
related to interest on escrows  described in the fifth paragraph,  Ocwen Federal
Bank FSB (the "Bank")complied with the minimum servicing standards identified in
the  Mortgage  Bankers   Association  of  America's   ("MBA's")  Uniform  Single
Attestation  Program for Mortgage  Bankers ("USAP") as of and for the year ended
December 31, 2003.  Management is  responsible  for the Bank's  compliance  with
those minimum servicing  standards.  Our responsibility is to express an opinion
on management's assertion about the Bank's compliance based on our examination.

     Our examination  was made in accordance  with standards  established by the
American  Institute of Certified Public Accountants and,  accordingly,  included
examining,  on a test  basis,  evidence  about the  Bank's  compliance  with the
minimum  servicing   standards  and  performing  other  such  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  the  Bank's  compliance  with  the  minimum  servicing
standards.

     Our examination  disclosed  noncompliance  with minimum servicing  standars
related to account  reconciliations  and interest on escrows  applicable  to the
Bank during the year ended December 31, 2003. Such noncompliance is described in
the accompanying Management Assertion on Compliance with USAP.

     In our opinion,  management's  assertion  that the Bank  complied  with the
aforementioned   minimum  servicing  standards,   except  for  noncompliance  as
described in the accompanying  Management  Assertion on Compliance with USAP, as
of and for the year ended  December 31, 2003 is fairly  stated,  in all material
respects.


By:  /s/PricewaterhouseCoopers, LLC
------------------------------------
PricewaterhouseCoopers, LLC

March 12, 2004


MANAGEMENT ASSERTON ON COMPLIANCE WITH USAP

March 12, 2004

As of and for the year ended  December 31, 2003,  except as  specifically  noted
below, Ocwen Federal Bank FSB (the "Bank") has complied in all material respects
with  the  minimum  servicing  standards  set  forth  in  the  Mortgage  Bankers
Assocation  of  America's  ("MBA's")  Uniform  Single  Attestation  Program  for
Mortgage Bankers ("USAP").

Standard: Reconciliations shall be prepared on a monthly basis for all custodial
bank accounts and related bank clearing accounts. These reconciliations shall be
mathematically accurate, be prepared within forty five (45) calendar days of the
cutoff  date;  be reviewed  and  approved  by someone  other than the person who
prepared  the   reconciliation;   and  document   explanations  for  reconciling
items.These reconciling items shall be resolved within ninety (90) calendar days
of their original identification.

Certain  reconciling  items which arose during the year ended  December 31, 2003
were not specifically  identified  and/or were not cleared with 90 days of their
original identification. Management has developed and implemented an action plan
and  continues  to  resolve  outstanding   reconciling  items.  All  significant
reconciling  items have been  isolated  and  reviewed  by the  Company,  and the
Company  believes  these items will not have a material  impact on the status of
any custodial accounts.

Standard:  Interest on escrow accounts shall be paid or credited,  to mortgagors
in accordance with the applicable state laws.

Interest on escrow  accounts in certain  states was not paid,  or  credited,  to
mortgagors in accordance  with the  applicable  state laws during the year ended
December 31, 2003.  The Bank has  corrected  the affected  accounts by paying or
crediting the appropriate interest on escrow. The bank is currently implementing
an enhancement to its REALServicingTM servicing system to ensure that, for loans
collateralized  by  properties  located in states  that  require  the payment of
interest  on  escrow  accounts,  the pay of  crediting  os cuch  interest  is in
accordance with applicable state laws.

As of and for this same  period,  the Bank had in effect a fidelity  bond in the
amount  of  $15,000,000  and an errors  and  omissions  policy in the  amount of
$5,000,000.



By: /s/ Ronald M. Faris
------------------------
Ronald M. Faris
President


By: /s/ Scott W. Andreson
-------------------------
Scott W. Andreson
Senior Vice President of Residential Assets


By: /s/ Brian J. LaForest
--------------------------
Brian J. LaForest
Director of Investor Reporting


Ocwen Federal Bank FSB
1675 Palm Beach Lakes Boulevard
West Palm Beach, FL  33401
P.O. Box 24737
West Palm Beach, FL  33416-4737

                                -11-

<PAGE>
EXHIBIT 99.2 - Annual Servicer's Statement of Compliance

 Chase Manhattan Mortgage Corporation, as Master Servicer
------------------------------------------------------------
                           OFFICER'S CERTIFICATION


Pursuant to Article III of the Pooling and Servicing Agreement,  the undersigned
Officers of Chase Manhattan Mortgage Corporation certifies to the following:

1.   A review of the  activities of Chase  Manhattan  Mortgage  Corporation,  as
     Master Servicer  during the preceding  calendar year and of its performance
     under the Master  Servicing  Agreement  has been made under such  officer's
     supervision.

2.   To the  best of such  Officer's  knowledge,  based  on such  review,  Chase
     Manhattan Mortgage Corporation has fulfilled all its obligations under this
     Agreement  throughout  such  year,  or, if there has been a default  in the
     fulfillment of any such  obligation,  specifying each such default known to
     such officer and the nature and status  thereof and the action being taking
     by Chase Manhattan Mortgage Corporation to cure such default.

CHASE MANHATTAN MORTGAGE CORP.


Certified By:   /s/  Diane Bentz                Date:  March 15, 2004
                ----------------------                 ---------------
                Diane Bentz
                Senior Vice President

                /s/  Michele L. Paul            Date:  March 15, 2004
                ----------------------                 ---------------
                Michele L. Paul
                Vice President

                                EXHIBIT A

Transaction                     Pooling and Servicing Agreement dated as of
-----------                     -------------------------------------------

CSFB 2003-AR1                   January 1, 2003
CSFB 2003-AR2                   January 1, 2003
CSFB 2003-AR5                   February 1, 2003
CSFB 2003-8                     March 1, 2003
CSFB 2003-AR9                   March 1, 2003
CSFB 2003-10                    April 1, 2003
CSFB 2003-11                    May 1, 2003
CSFB 2003-AR12                  April 1, 2003
CSFB 2003-AR15                  May 1, 2003
CSFB 2003-17                    June 1, 2003
CSFB 2003-AR18                  July 1, 2003
CSFB 2003-AR20                  July 1, 2003
CSFB 2003-AR22                  August 1, 2003
CSFB 2003-AR24                  September 1, 2003
CSFB 2003-AR26                  October 1, 2003
CSFB 2003-AR28                  November 1, 2003


                                -12-


<PAGE>

Washington Mutual Mortgage Securities Corp., as Servicer
----------------------------------------------------------


                     CSFB MORTGAGE PASS-THROUGH CERTIFICATES
                                   SERIES 2003-AR12

                              OFFICER'S CERTIFICATE


     I,  Michael L.  Parker,  a duly  elected and acting  officer of  Washington
Mutual Mortgage Securities Corp. (the "Servicer"), certify to Bank One, National
Association (the "Trustee"),  Chase Manhattan Mortgage  Corporation (the "Master
Servicer")  and Credit  Suisse  First  Boston  Mortgage  Securities  Corp.  (the
"Depositor")  and each Person,  if any, who "controls" the Depositor  within the
meaning of the Securities Act of 1933, as amended, and their respective officers
and directors,  with respect to the calendar year immediately preceding the date
of this certificate (the "Relevant Year"), as follows:

     1. For  purposes  of this  certificate,  "Relavant  Information"  means the
information in the certificate (the "Annual  Compliance  Certificate")  provided
pursuant  to Section  3.16 of the Pooling and  Servicing  Agreement  dated as of
April  1,  2003  (the  "Pooling  and  Servicing  Agreement")  by and  among  the
Depositor,  as  depositor,  the  Servicer,  as  master  servicer,  and Bank One,
National  Association,  as  trustee,  and in  the  accountant's  statement  (the
"Accountant's  Statement")  provided pursuant to Section 3.17 of the Pooling and
Servicing Agreement, for the Relevant Year, and the information in all servicing
reports  provided by the  Servicer  pursuant to Section  4.04 of the Pooling and
Servicing  Agreement  during  the  Relevant  Year.  Based on my  knowledge,  the
Relevant Information, taken as a whole, does not contain any untrue statement of
a material fact or omit to state a material  fact required to be stated  therein
which is necessary to make the statements therein, in light of the circumstances
under which such  statements were made, not misleading as of the last day of the
Relevant Year.

     2. The Relevant  Information has been provided to those Persons entitled to
receive it.

     3. I am responsible for reviewing the activities  performed by the Servicer
under the Pooling and Servicing  Agreement  during the Relevant Year. Based upon
review  required by the Pooling and Servicing  Agreement and except as disclosed
in the Annual Compliance Certificate or the Accountants'  Statement, to the best
of my knowledge,  the Servicer has fulfilled its  obligations  under the Pooling
and Servicing Agreement throughout the Relavant Year.

DATED: March 15, 2004


                                        By:  /s/ Michael L. Parker
                                        --------------------------
                                        Name:   Michael L. Parker
                                        Title:  President and COO


                                     -13-

<PAGE>
 Cendant Mortgage Corporation, as Servicer
-----------------------------------------
                              CENDANT

                        OFFICER'S CERTIFICATE

                               2003-AR12


     Pursuant  to  Article  III of the  Pooling  and  Servicing  Agreement,  the
undersigned Officer of CENDANT certifies to the following:

     1. A  review  of the  activities  of such  Servicer  during  the  preceding
calendar year and of the  performance  of such Servicer under this Agreement has
been made under such officer's supervision, and.

     2. To the best of such  officer's  knowledge,  based on such  review,  such
Servicer has fulfilled all its obligations under this Agreement  throughout such
year, or if there has been a default in the fulfillment of any such  obligation,
specifying  each such  default  known to such  officer and the nature and status
thereof and the action being taken by such Servicer to cure such default.

CENDANT

Certified By:  /s/  Marc J. Kinkle                   Date:  3-19-04
               ----------------------                   ---------------
                 Marc J. Kinkle
                 Vice President-Servicing

                                -14-

<PAGE>

                         (officer's certification)

Fairbanks Capital Corp.

3815 South West Temple
Salt Lake City, Utah  84115-4412
P.O. Box 65250
Salt Lake City, Utah  84165-0250
telephone (801) 293-1883
fax (801) 293-1297



Agreement:      See Schedule of Agreements

Dated:          See Attached Schedule

                ANNUAL STATEMENT AS TO COMPLIANCE

In  accordance  with  applicable  section in each of the Pooling  and  Servicing
Agreements specified:

i.   a review of the  activities of the Servicer  during the year ended December
     31, 2003 and of  performance  under this Agreement has been made under such
     officers' supervision; and

ii.  to the  best of such  officers'  knowledge,  based  on  such  review,  the
     Servicer  has  fulfilled  all  of  its  obligations  under  this  Agreement
     throughout such year.

February 6, 2004

                                        /s/ Matt Hollingsworth
                                        ----------------------------
                                        Matt Hollingsworth
                                        Chief Operating Officer
                                        Fairbanks Capital Corp.

SCHEDULE OF AGREEMENTS

                                        -15-


<PAGE>
 Ocwen Federal Bank FSB, as Servicer
---------------------------------------

Ocwen Federal Bank FSB
1675 Palm Beach Lakes Boulevard
West Palm Beach, FL  33401
P.O. Box 24737
West Palm Beach, FL  33416-4737





                      OCWEN FEDERAL BANK FSB
          Compliance Certification Year ended December 31, 2003
           CSFB Mtg-Backed PT Certificates, Series 2003-AR12


The  undersigned  Officer of Ocwen Federal Bank FSB, (the  "Serivcer")  confirms
that (i) a review of the  activities  of the Servicer  during the calendar  year
ending on Decembe  31, 2003 and of the  performance  of the  Servicer  under the
Pooling and Servicing  Agreement for Mortgage-Backed  Pass-Through  Certificates
Series  2003-AR12 dated April 1, 2003 (the "Servicing  Agreement") has been made
under his supervision. Except as noted on the Management Assertion on Compliance
with USAP, to the best of the undersigned Officers knowledge, bason such review,
the Servicer has fulfilled  all of its  obligation as set forth in the Servicing
Agreement.



By:  /s/ Scott W. Anderson                      Dated:  March 12, 2004
----------------------------------------
Scott W. Anderson, Senior Vice President

                                        -16-