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, 2005
                                      -----------------

                                       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: 333-117949-32
                                              -------------


                 CWALT, Inc., Alternative Loan Trust 2005-18CB,
              Mortgage Pass-Through Certificates, Series 2005-18CB
              ----------------------------------------------------
             (Exact name of Registrant as specified in its charter)


              Delaware                                  87-0698307
------------------------------------       ------------------------------------
(State or other jurisdiction of            (I.R.S. Employer Identification No.)
incorporation or organization)

c/o      Countrywide Home Loans Servicing LP
         4500 Park Granada
         Calabasas, California                            91302
----------------------------------------   ------------------------------------
(Address of principal executive offices)                (Zip Code)

Registrant's telephone number, including area code:   (818) 225-3000
                                                      --------------

Securities registered pursuant to Section 12(b) of the Act:  None
                                                             ----

Securities registered pursuant to Section 12(g) of the Act:  None
                                                             ----



<PAGE>



      Indicate by check mark if the registrant is a well-known  seasoned issuer,
as defined in Rule 405 of the Securities Act. [ ] Yes [X] No

      Indicate by check mark if the  registrant  is not required to file reports
pursuant to Section 13 or Section 15(d) of the Act. [ ] Yes [X] No

      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. [X] Yes [ ] No

      Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K (ss.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. [X]

      Indicate  by check mark  whether  the  registrant  is a large  accelerated
filer,  an accelerated  filer,  or a  non-accelerated  filer.  See definition of
"accelerated  filer and large  accelerated  filer" in Rule 12b-2 of the Exchange
Act. (Check one):

Large accelerated filer [  ]  Accelerated filer [ ]  Non-accelerated filer [X]

      Indicate  by check mark  whether  the  registrant  is a shell  company (as
defined in Rule 12b-2 of the Act). [ ] Yes [X] No

      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



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<PAGE>



                      DOCUMENTS INCORPORATED BY REFERENCE

                                     None.

                                     *  *  *


      This Annual  Report on Form 10-K (the  "Report")  is filed with respect to
the trust fund  entitled  Alternative  Loan Trust  2005-18CB  (the "Trust Fund")
formed pursuant to the pooling and servicing agreement dated as of March 1, 2005
(the "Pooling and Servicing  Agreement")  among CWALT,  Inc., as depositor  (the
"Company"), Countrywide Home Loans, Inc., as a seller (a "Seller"), Park Granada
LLC, as a seller (a "Seller"),  Park Sienna LLC, as a seller (a "Seller"),  Park
Monaco Inc., as a seller (a "Seller"),  Countrywide  Home Loans Servicing LP, as
master servicer (the "Master Servicer"),  Federal National Mortgage Association,
as guarantor of the Class A-1, Class A-2, Class A-3 and Class A-4  Certificates,
and The Bank of New York, as trustee (the "Trustee"), for the issuance of CWALT,
Inc., Mortgage Pass-Through Certificates, Series 2005-18CB (the "Certificates").
Certain  information  otherwise  required  to be  included in this Report by the
Instructions  to Form 10-K has been omitted in reliance on the relief granted by
the Commission to other companies in similar circumstances,  in particular,  the
relief  granted in CWMBS,  Inc.  (February 3, 1994)  (collectively,  the "Relief
Letters").


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<PAGE>

                                     PART I


Item 1.     Business.

            Not applicable. See the Relief Letters.

Item 1A. Risk Factors.

            Not applicable.

Item 1B.    Unresolved Staff Comments.

            None.

Item 2.     Properties.

            Not applicable. See the Relief Letters.

Item 3.     Legal Proceedings.

            There were no material  pending  legal  proceedings  relating to the
            Trust Fund to which any of the Trust Fund,  the Trustee,  the Master
            Servicer  or the  Company  was a  party  or of  which  any of  their
            respective properties was the subject during the fiscal year covered
            by this Report other than ordinary routine litigation  incidental to
            the duties of the Trust Fund,  the Trustee,  the Master  Servicer or
            the  Company,  nor is the  Company  aware  of any  such  proceedings
            contemplated by governmental authorities.

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

            No matter  was  submitted  to a vote of  Certificateholders,  and no
            Certificateholder  consent  was  solicited  during the  fiscal  year
            covered by this Report.



                                       4
<PAGE>



                                     PART II


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

            (a)   Item 201 of Regulation S-K:

                  i.    Market  Information.  There  is  no  established  public
                        trading market for the Certificates.

                  ii.   Holders.  As of  December  31, 2005 there were less than
                        300 holders of record of the Certificates.


                  iii.  Dividends.  Not  applicable.  See  the  Relief  Letters.
                        (Information as to distributions  to  Certificateholders
                        is provided in the Registrant's  monthly filings on Form
                        8-K.)

                  iv.   Securities   Authorized   for   Issuance   Under  Equity
                        Compensation Plans. Not applicable.

                  Item 701 of Regulation S-K. Not applicable.

            (b)   Rule 463 of the Securities Act of 1933. Not applicable.

            (c)   Item 703 of Regulation  S-K. Not  applicable as the Registrant
                  has no class  of  equity  securities  registered  pursuant  to
                  section 12 of the Securities Exchange Act of 1934.

Item 6.     Selected Financial Data.

            Not applicable.  See the Relief Letters.

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

            Not applicable.  See the Relief Letters.

Item 7A     Quantitative and Qualitative Disclosures about Market Risk.

            Not applicable.

Item 8.     Financial Statements and Supplementary Data.

            Not applicable.  See the Relief Letters.


                                       5
<PAGE>


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.


                                       6
<PAGE>



                                    PART III


Item 10.    Directors and Executive Officers of the Registrant.

            Not applicable. See the Relief Letters.

Item 11.    Executive Compensation.

            Not applicable. See the Relief Letters.

Item 12.    Security Ownership of Certain Beneficial Owners, Management and
            Related Stockholder Matters.

            Information   required  by  Item  201(d)  of  Regulation   S-K:  Not
            applicable.

            Information required by Item 403 of Regulation S-K:

            (a)   Not applicable. See the Relief Letters.

            (b)   Not applicable. See the Relief Letters.

            (c)   Not applicable. See the Relief Letters.

Item 13.    Certain Relationships and Related Transactions.

            Not applicable. See the Relief Letters.

Item 14.    Principal Accounting Fees and Services.

            Not applicable.

                                       7
<PAGE>



                                     PART IV


Item 15.    Exhibits and Financial Statement Schedules.

            (a)   (1)   Pursuant to the Pooling and Servicing Agreement, the
                        Master  Servicer  is  required  (i) to deliver an annual
                        statement as to  compliance  with the  provisions of the
                        Pooling  and  Servicing   Agreement  and  certain  other
                        matters (the "Annual  Statement of the Master Servicer")
                        and  (ii)  to  cause  a  firm  of   independent   public
                        accountants to deliver an annual report as to compliance
                        with  the  servicing   provisions  of  the  Pooling  and
                        Servicing  Agreement  (the "Annual Report of the Firm of
                        Accountants").   The  Annual  Statement  of  the  Master
                        Servicer is attached as Exhibit 99.1 to this Report. The
                        Annual Report of the Firm of  Accountants is attached as
                        Exhibit 99.2 to this Report. See Relief Letters.

                  (2)   Not applicable.

                  (3)   The required exhibits are as follows:

                        o     Exhibit  3(i):  Copy of Company's  Certificate  of
                              Incorporation (Filed as an Exhibit to Registration
                              Statement on Form S-3 (File No. 333-110343)).

                        o     Exhibit 3(ii): Copy of Company's By-laws (Filed as
                              an Exhibit to  Registration  Statement on Form S-3
                              (File No. 333-110343)).

                        o     Exhibit 4: Pooling and Servicing  Agreement (Filed
                              as part of the Registrant's Current Report on Form
                              8-K filed on July 13, 2005).

                        o     Exhibit 31: Rule 15d-14(a) Certification.

                        o     Exhibit  99.1:  Annual  Statement  of  the  Master
                              Servicer.

                        o     Exhibit  99.2:   Annual  Report  of  the  Firm  of
                              Accountants.

            (b)   See subparagraph (a)(3) above.

            (c)   Not applicable. See the Relief Letters.



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<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.

                                    CWALT, INC.,
                                    ALTERNATIVE LOAN TRUST 2005-18CB,
                                    MORTGAGE PASS-THROUGH CERTIFICATES,
                                    SERIES 2005-18CB

                                    By:   Countrywide Home Loans Servicing LP,
                                          as Master Servicer*

                                    By:   Countrywide GP, Inc.


                                    By:   /s/ Craig Baingo
                                          ---------------------------
                                          Name:  Craig Baingo
                                          Title:    Executive Vice President

                                    Date: March 27, 2006


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

*     This Report is being  filed by the Master  Servicer on behalf of the Trust
      Fund. The Trust Fund does not have any officers or directors.



                                       9
<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.

      No such annual report, proxy statement,  form of proxy or other soliciting
material  has  been,  or will be,  sent to  Certificateholders.  See the  Relief
Letters.


                                       10
<PAGE>



                                 EXHIBIT INDEX



Exhibit           Document
-------           --------

3(i)              Company's Certificate of Incorporation (Filed as an Exhibit to
                  Registration Statement on Form S-3 (File No. 333-110343))*

3(ii)             Company's By-laws (Filed as an Exhibit to Registration
                  Statement on Form S-3 (File No. 333-110343)*

4                 Pooling and Servicing Agreement (Filed as part of the
                  Company's Current Report on Form 8-K filed on July 13, 2005)*

31                Rule 15d-14(a) Certification

99.1              Annual Statement of the Master Servicer

99.2              Annual Report of the Firm of Accountants

-----------
*     Incorporated herein by reference.

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