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    period  from October 1, 2001
         (Commencement of Operations) to December 31, 2001

[  ]     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 333-61840-08

               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 PASS-THROUGH CERTIFICATES, SERIES 2001-S23
       (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]

Documents incorporated by reference:  None

                                   Page 1 of 5
             This report consists 8 of consecutively numbered pages.


<PAGE>

CREDIT SUISSE FIRST BOSTON MORTGAGE SECURITIES CORP.
CSFB
MORTGAGE PASS-THROUGH CERTIFICATES, SERIES 2001-S23
-----------------------------------------------------------------------
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 or the Trustee, 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,  2001,  the number
of holders  of each  Class  of  Offered  Certificates was 10.


Item 6.  Selected Financial Data

         Omitted.

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

         Omitted.

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.

                                      -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.


PART IV

Item 14. 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  Servicer  Statement of  Compliance,  filed as Exhibit 99.1 hereto.
   Annual Statement of  Independent  Accountants  Report for the Servicer,
           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 2001.

      Current  Reports   on Form 8-K,   dated   November 26,  2001, December 26,
     2001,  and  January  25,  2002,   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 (Other Events).


(c)   Exhibits to this report are listed in Item (14)(a)(3) above.

                                      -3-
<PAGE>


SIGNATURE

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.


                                    JPMORGAN CHASE BANK,
                                    not in its individual capacity but solely
                                    as Trustee under the Agreement
                                    referred to herein



Date:  March 28, 2002               By:  /s/ Thomas M. Britt
                                    -----------------------------
                                    Thomas M. Britt
                                    Trust Officer



                                      -4-
<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.

                                      -5-
<PAGE>


                                 EXHIBIT INDEX

Exhibit     Description

 99.1       Servicer's Annual Statement of Compliance
 99.2       Servicer's Annual Independent Accountant's Report



                                      -6-
<PAGE>




EXHIBIT 99.1 - Servicer's Annual Statement of Compliance
  To be supplied upon receipt by the Trustee

                                      -7-


EXHIBIT 99.2 - Servicer's Annual Independent Accountant's Report
  To be supplied upon receipt by the Trustee

                                      -8-