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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549



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FORM 10-K/A

Amendment No. 1



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|x | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
|- | ------------------------------------------------------------------------------------

For the fiscal year ended December 31, 2006

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
No. 000-51579



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LOGO

NCI, INC.

(Exact name of registrant as specified in its charter)



|                                                               |  |                                     
|-------------------------------------------------------------- |  | ------------------------------------
|Delaware                                                       |  | 20-3211574                          
|(State or other jurisdiction of incorporation or organization) |  | (I.R.S. Employer Identification No.)
|                                                               | 
|11730 Plaza America Drive Reston, Virginia                     |  | 20190-4764                          
|(Address of principal executive offices)                       |  | (Zip Code)                          

Registrants telephone number, including area code: (703) 707-6900



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

None

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

Class A Common Stock, par value $0.019 per share



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

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

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 the 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  x                    Non-accelerated filer ̈

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

The aggregate market value of NCI, Inc. Class A common stock held by non-affiliates of the registrant as of June 30, 2006 was
$77,449,610.

As of March 1, 2007, there were 7,027,760 shares outstanding of the registrants Class A common stock. In
addition, there are 6,300,000 shares outstanding of the registrants Class B common stock, which are convertible on a one-for-one basis into Class A common stock.

DOCUMENTS INCORPORATED BY REFERENCE

Certain portions of the definitive Proxy
Statement to be filed with the Securities Exchange Commission pursuant to Regulation 14A in connection with the registrants 2007 Annual Meeting of Stockholders, to be filed subsequent to the date hereof, are incorporated by reference into Part
III (Items 10, 11, 12, 13 and 14) of this Annual Report on Form 10-K. Such definitive Proxy Statement will be filed with the Commission not later than 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K.



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EXPLANATORY NOTE

This Amendment No. 1 to the Annual Report on Form 10-K of NCI, Inc. (the Company) is being filed solely to amend Exhibits 31.1, 31.2, 32.1, and 32.2 (Certifications Pursuant to Section 302 and
Section 906 of the Sarbanes-Oxley Act of 2002) to correct certain typographical errors in the certifications.

Except as described
above, no other changes have been made to the original Form 10-K, and this Form 10-K/A does not amend, update or change the financial statements or any other items or disclosures in the original Form 10-K. This Form 10-K/A does not reflect events
occurring after the filing of the Form 10-K or modify or update those disclosures, including any exhibits to the Form 10-K affected by subsequent events. Information not affected by the changes described above is unchanged and reflects the
disclosures made at the time of the original filing of the Form 10-K on March 9, 2007. Accordingly, this Form 10-K/A should be read in conjunction with our filings made with the Securities and Exchange commission subsequent to the filing of the
original Form 10-K, including any amendments to those filings.



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PART IV



|ITEM 15. | EXHIBITS AND FINANCIAL STATEMENT SCHEDULES
|-------- | ------------------------------------------



| | (a) | The following documents are filed as a part of this annual report on Form 10-K/a:
| | --- | ---------------------------------------------------------------------------------



| | (3) | Exhibits required by Item 601 of Regulation S-K:
| | --- | ------------------------------------------------



|       |  |                                                                                                                                                       
|------ |  | ------------------------------------------------------------------------------------------------------------------------------------------------------
|Number |  | Description                                                                                                                                           
|31.1  |  | Certification of the Chief Executive Officer pursuant to rule 13a-14(a) of the Securities Exchange Act of 1934, as amended.                           
|31.2  |  | Certification of the Chief Financial Officer pursuant to rule 13a-14(a) of the Securities Exchange Act of 1934, as amended.                           
|32.1  |  | Certification of the Chief Executive Officer pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.
|32.2  |  | Certification of the Chief Financial Officer pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

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| | Included with this filing.
|- | --------------------------



| | (b) | Exhibits. The exhibits required by this Item are listed under Item 15(a)(3).
| | --- | ----------------------------------------------------------------------------





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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.



|                     |  |  |  |                      |  |                        |  |                                                                                                              
|-------------------- |  |  |  | -------------------- |  | ---------------------- |  | -------------------------------------------------------------------------------------------------------------
|                     |  |  |  | NCI, Inc. Registrant
|                     |  |  | 
|Date: March 16, 2007 |  |  |  | By:                  |  | /s/ JUDITH L. BJORNAAS
|                     |  |  |  |                      |  |                        |  | Judith L. Bjornaas Senior Vice
President Chief Financial Officer (Principal
Financial and Accounting Officer)