UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

________________

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest Event

Reported): January 18, 2008

CHL Mortgage Pass-Through Trust 2007-21

(Exact name of the issuing entity)

Commission File Number of the issuing entity: 333-140958-23

CWMBS, Inc.

(Exact name of the depositor as specified in its charter)

Commission File Number of the depositor: 333-140958

Countrywide Home Loans Inc.

(Exact name of the sponsor as specified in its charter)

Delaware	95-4449516
(State or Other Jurisdiction	(I.R.S. Employer
of Incorporation of the depositor)	Identification No. of the depositor)

4500 Park Granada Calabasas, California	91302
(Address of Principal Executive Offices of the depositor)	(Zip Code)

The depositor’s telephone number, including area code (818) 225-3000

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any following provisions:

o	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o	Soliciting material pursuant to Rule 14a-12(b) under the Exchange Act (17 CFR 240.14a-12(b))

o	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01. Other Events.

The tables attached hereto as Exhibit 99.1 describe characteristics of the mortgage loans in loan group 1 and loan group 2 following the transfer to the issuing entity of all Supplemental Mortgage Loans during the Funding Period as of the related cut-off date. All percentages set forth below have been calculated based on the aggregate Stated Principal Balance of the mortgage loans in the related loan group as of the related cut-off date. The sum of the columns may not equal the respective totals due to rounding.

Capitalized terms used but not defined herein shall have the respective meanings assigned to them in the related prospectus supplement, as filed with the Securities and Exchange Commission on December 31, 2007 under Rule 424(b)(5).

Item 9.01. Financial Statements and Exhibits.

(a)	Not applicable.

(b)	Not applicable.

(c)

Exhibits:

Exhibit No. Description

99.1

Characteristics of the mortgage loans in loan group 1 and loan group 2 after the Funding Period.

Signatures

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

CWMBS, INC.

By: /s/ Darren Bigby

Name: Darren Bigby

Title: Executive Vice President

Dated: January 24, 2008

Exhibit Index

Exhibit No. Description

99.1	Characteristics of the mortgage loans in loan group 1 and loan group 2 after the Funding Period.

CHL Mortgage Pass-Through Trust 2007-21 8-K