Form N-Q

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549

FORM N-Q


QUARTERLY SCHEDULE OF PORTFOLIO HOLDINGS OF REGISTERED MANAGEMENT INVESTMENT COMPANY

Investment Company Act file number         811-21212         

        Nuveen Insured California Tax-Free Advantage Municipal Fund         
(Exact name of registrant as specified in charter)


        333 West Wacker Drive, Chicago, Illinois 60606         
(Address of principal executive offices) (Zip code)


Jessica R. Droeger—Vice President and Secretary
        333 West Wacker Drive, Chicago, Illinois 60606         
(Name and address of agent for service)

Registrant's telephone number, including area code:         312-917-7700        

Date of fiscal year end:            8/31          

Date of reporting period:          11/30/05         

Form N-Q is to be used by management investment companies, other than small business investment companies registered on Form N-5 (§§ 239.24 and 274.5 of this chapter), to file reports with the Commission, not later than 60 days after the close of the first and third fiscal quarters, pursuant to rule 30b1-5 under the Investment Company Act of 1940 (17 CFR 270.30b1-5). The Commission may use the information provided on Form N-Q in its regulatory, disclosure review, inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-Q, and the Commission will make this information public. A registrant is not required to respond to the collection of information contained in Form N-Q unless the Form displays a currently valid Office of Management and Budget (“OMB”) control number. Please direct comments concerning the accuracy of the information collection burden estimate and any suggestions for reducing the burden to the Secretary, Securities and Exchange Commission, 450 Fifth Street, NW, Washington, DC 20549-0609. The OMB has reviewed this collection of information under the clearance requirements of 44 U.S.C. § 3507.

Item 1. Schedule of Investments

  Portfolio of Investments (Unaudited)
Nuveen Insured California Tax-Free Advantage Municipal Fund (NKX)
November 30, 2005

Principal    Optional Call    Market 
Amount (000)  Description(1)   Provisions*  Ratings**  Value 
  Consumer Staples - 2.3% (1.5% of Total Investments)       
$ 1,625  Golden State Tobacco Securitization Corporation, California, Tobacco Settlement Asset-Backed  6/13 at 100.00  BBB  $ 1,958,011 
  Revenue Bonds, Series 2003A-2, 7.900%, 6/01/42       
  Healthcare - 15.3% (10.3% of Total Investments)       
1,500  California Health Facilities Financing Authority, Revenue Bonds, UCSF - Stanford Healthcare, Series  11/08 at 101.00  AAA  1,542,825 
  1998A, 5.000%, 11/15/31 - FSA Insured       
1,800  California Infrastructure Economic Development Bank, Revenue Bonds, Kaiser Hospital Assistance LLC,  8/11 at 102.00  A+  1,880,476 
  Series 2001A, 5.550%, 8/01/31       
6,000  California Statewide Community Development Authority, Revenue Bonds, Sherman Oaks Health System,  No Opt. Call  AAA  6,356,040 
  Series 1998A, 5.000%, 8/01/22 - AMBAC Insured       
2,000  California Statewide Community Development Authority, Hospital Revenue Bonds, Monterey Peninsula  6/13 at 100.00  AAA  2,116,140 
  Hospital, Series 2003B, 5.250%, 6/01/23 - FSA Insured       
1,260  Rancho Mirage Joint Powers Financing Authority, California, Revenue Bonds, Eisenhower Medical  7/14 at 100.00  A3  1,342,933 
  Center, Series 2004, 5.875%, 7/01/26       
  Housing/Multifamily - 1.3% (0.9% of Total Investments)       
1,165  Poway, California, Housing Revenue Bonds, Revenue Bonds, Poinsettia Mobile Home Park, Series 2003,  5/13 at 102.00  BBB+  1,167,994 
  5.000%, 5/01/23       
  Long-Term Care - 5.8% (3.9% of Total Investments)       
1,000  ABAG Finance Authority for Non-Profit Corporations, California, Insured Senior Living Revenue  11/12 at 100.00  A  1,040,860 
  Bonds, Odd Fellows Home of California, Series 2003A, 5.200%, 11/15/22       
2,000  California Health Facilities Financing Authority, Cal-Mortgage Insured Revenue Bonds, Northern  1/13 at 100.00  A  2,084,520 
  California Retired Officers Community Corporation - Paradise Valley Estates, Series 2002, 5.250%,       
  1/01/26       
1,815  California Statewide Community Development Authority, Revenue Bonds, Jewish Home for the Aging,  11/13 at 100.00  A  1,881,865 
  Series 2003, 5.000%, 11/15/18       
  Tax Obligation/General - 48.7% (32.8% of Total Investments)       
1,000  Berryessa Union School District, Santa Clara County, California, General Obligation Bonds, Series  8/12 at 100.00  AAA  1,051,160 
  2003C, 5.000%, 8/01/21 - FSA Insured       
2,000  Butte-Glenn Community College District, Butte and Glenn Counties, California, General Obligation  8/12 at 101.00  Aaa  2,077,940 
  Bonds, Series 2002A, 5.000%, 8/01/26 - MBIA Insured       
  California, General Obligation Refunding Bonds, Series 2002:       
1,500  5.000%, 2/01/12  No Opt. Call  A  1,601,490 
3,750  5.000%, 4/01/27 - AMBAC Insured  4/12 at 100.00  AAA  3,867,788 
3,000  5.250%, 4/01/30 - XLCA Insured  4/12 at 100.00  AAA  3,142,020 
500  California, General Obligation Bonds, Series 2004, 5.250%, 4/01/34  4/14 at 100.00  A  521,735 
450  Fremont Unified School District, Alameda County, California, General Obligation Bonds, Series  8/12 at 101.00  AAA  468,369 
  2002A, 5.000%, 8/01/25 - FGIC Insured       
  Hacienda La Puente Unified School District, Los Angeles County, California, General Obligation       
  Bonds, Series 2003B:       
4,500  5.000%, 8/01/26 - FSA Insured  8/13 at 100.00  AAA  4,675,365 
2,030  5.000%, 8/01/27 - FSA Insured  8/13 at 100.00  AAA  2,105,090 
2,000  Los Angeles, California, General Obligation Bonds, Series 2002A, 5.000%, 9/01/22 - MBIA Insured  9/12 at 100.00  AAA  2,095,020 
565  Los Angeles Community College District, Los Angeles County, California, General Obligation Bonds,  8/15 at 100.00  AAA  591,657 
  Series 2005A, 5.000%, 6/01/26 - FSA Insured       
10,500  Los Angeles Unified School District, California, General Obligation Bonds, Series 2003A, 5.000%,  7/13 at 100.00  AAA  11,071,935 
  7/01/22 - FSA Insured       
1,000  Murrieta Valley Unified School District, Riverside County, California, General Obligation Bonds,  9/13 at 100.00  AAA  1,039,320 
  Series 2003A, 5.000%, 9/01/26 - FGIC Insured       
  Oakland Unified School District, Alameda County, California, General Obligation Bonds, Series 2005:       
190  5.000%, 8/01/25 - MBIA Insured  8/15 at 100.00  AAA  198,508 
200  5.000%, 8/01/26 - MBIA Insured  8/15 at 100.00  AAA  208,796 
3,000  San Diego Unified School District, California, General Obligation Bonds, Election of 1998, Series  7/10 at 100.00  AAA  3,192,390 
  2000B, 5.125%, 7/01/22 - MBIA Insured       
  San Jose-Evergreen Community College District, Santa Clara County, California, General Obligation       
  Bonds, Series 2005A:       
145  5.000%, 9/01/25 - MBIA Insured  9/15 at 100.00  AAA  152,005 
215  5.000%, 9/01/27 - MBIA Insured  9/15 at 100.00  AAA  224,692 
3,855  San Rafael City High School District, Marin County, California, General Obligation Bonds, Series  8/12 at 100.00  AAA  3,979,324 
  2003A, 5.000%, 8/01/28 - FSA Insured       
  Tax Obligation/Limited - 42.9% (28.9% of Total Investments)       
550  Baldwin Park Public Financing Authority, California, Sales Tax and Tax Allocation Bonds, Puente  8/13 at 102.00  BBB  572,127 
  Merced Redevelopment Project, Series 2003, 5.250%, 8/01/21       
2,025  Burbank Public Financing Authority, California, Revenue Refunding Bonds, Golden State Redevelopment  12/13 at 100.00  AAA  2,168,957 
  Project, Series 2003A, 5.250%, 12/01/22 - AMBAC Insured       
4,000  California State Public Works Board, Lease Revenue Bonds, Department of General Services, Capital  12/12 at 100.00  AAA  4,105,720 
  East End Project, Series 2002A, 5.000%, 12/01/27 - AMBAC Insured       
2,000  California State Public Works Board, Lease Revenue Bonds, Department of Corrections, Series 2003C,  12/13 at 100.00  A-  2,165,980 
  5.500%, 6/01/16       
1,610  Folsom Public Financing Authority, California, Special Tax Revenue Bonds, Series 2004A, 5.000%,  9/12 at 102.00  AAA  1,687,183 
  9/01/21 - AMBAC Insured       
130  Hesperia Community Redevelopment Agency, California, Tax Allocation Bonds, Series 2005A, 5.000%,  9/15 at 100.00  AAA  136,913 
  9/01/20 - XLCA Insured       
5,540  Irvine Public Facilities and Infrastructure Authority, California, Assessment Revenue Bonds, Series  3/06 at 103.00  AAA  5,725,091 
  2003C, 5.000%, 9/02/21 - AMBAC Insured       
2,000  Los Angeles, California, Certificates of Participation, Municipal Improvement Corporation, Series  6/13 at 100.00  AAA  2,043,280 
  2003AW, 5.000%, 6/01/33 - AMBAC Insured       
1,770  Los Angeles Unified School District, California, Certificates of Participation, Administration  10/12 at 100.00  AAA  1,815,719 
  Building Project II, Series 2002C, 5.000%, 10/01/27 - AMBAC Insured       
1,500  Los Osos, California, Improvement Bonds, Community Services Wastewater Assessment District 1,  9/10 at 103.00  AAA  1,531,455 
  Series 2002, 5.000%, 9/02/33 - MBIA Insured       
500  Paramount Redevelopment Agency, California, Tax Allocation Bonds, Redevelopment Project Area 1,  8/13 at 100.00  AAA  524,795 
  Series 2003, 5.000%, 8/01/19 - MBIA Insured       
150  Rialto Redevelopment Agency, California, Tax Allocation Bonds, Merged Project Area, Series 2005A,  9/15 at 100.00  AAA  152,714 
  5.000%, 9/01/35 - XLCA Insured       
315  Riverside County Public Financing Authority, California, Tax Allocation Bonds, Multiple Projects,  10/15 at 100.00  AAA  321,234 
  Series 2005A, 5.000%, 10/01/35 - XLCA Insured       
  San Buenaventura, California, Certificates of Participation, Golf Course Financing Project, Series      
  2002D:      
3,000  5.000%, 2/01/27 - AMBAC Insured 2/12 at 100.00  AAA  3,070,920 
3,300  5.000%, 2/01/32 - AMBAC Insured 2/12 at 100.00  AAA  3,363,426 
1,200  San Diego Redevelopment Agency, California, Subordinate Lien Tax Increment and Parking Revenue 9/09 at 101.00  Baa2  1,236,420 
  Bonds, Centre City Project, Series 2003B, 5.250%, 9/01/26      
1,220  San Jose Redevelopment Agency, California, Tax Allocation Bonds, Merged Area Redevelopment Project, 8/10 at 101.00  AAA  1,241,167 
  Series 2002, 5.000%, 8/01/32 - MBIA Insured      
2,770  San Jose Financing Authority, California, Lease Revenue Refunding Bonds, Civic Center Project, 6/12 at 100.00  AAA  2,824,957 
  Series 2002B, 5.000%, 6/01/32 - AMBAC Insured      
2,390  Solano County, California, Certificates of Participation, Series 2002, 5.250%, 11/01/24 - MBIA 11/12 at 100.00  AAA  2,550,202 
  Insured      
  Transportation - 13.9% (9.4% of Total Investments)      
5,480  Bay Area Governments Association, California, BART SFO Extension, Airport Premium Fare Revenue 8/12 at 100.00  AAA  5,628,070 
  Bonds, Series 2002A, 5.000%, 8/01/26 - AMBAC Insured      
2,000  Foothill/Eastern Transportation Corridor Agency, California, Toll Road Revenue Bonds, Series 1995A, 1/10 at 100.00  BBB-  1,873,480 
  5.000%, 1/01/35      
3,135  San Francisco Airports Commission, California, Revenue Bonds, San Francisco International Airport, 5/08 at 101.00  AAA  3,243,596 
  Second Series Issue 16B, 5.000%, 5/01/24 - FSA Insured      
1,300  San Francisco Airports Commission, California, Revenue Bonds, San Francisco International Airport, 5/10 at 101.00  AAA  1,352,000 
  Second Series 2000, Issue 26B, 5.000%, 5/01/25 - FGIC Insured      
  U.S. Guaranteed*** - 1.3% (0.9% of Total Investments)      
1,000  California Health Facilities Financing Authority, Revenue Bonds, Cedars-Sinai Medical Center, 12/09 at 101.00  A3***  1,114,750 
  Series 1999A, 6.250%, 12/01/34 (Pre-refunded to 12/01/09)      
  Utilities - 5.7% (3.8% of Total Investments)      
1,000  Anaheim Public Finance Authority, California, Second Lien Electric Distribution Revenue Bonds, 10/14 at 100.00  AAA  1,074,870 
  Series 2004, 5.250%, 10/01/21 - MBIA Insured      
3,055  Los Angeles Department of Water and Power, California, Power System Revenue Bonds, Series 2001A-1, 7/11 at 100.00  AAA  3,245,143 
  5.250%, 7/01/22 - FSA Insured      
275  Los Angeles Department of Water and Power, California, Power System Revenue Bonds, Series 2003A-2, 7/13 at 100.00  AAA  290,326 
  5.000%, 7/01/21 - MBIA Insured      
310  Merced Irrigation District, California, Electric System Revenue Bonds, Series 2005, 5.125%, 9/15 at 100.00  AAA  320,804 
  9/01/31 - XLCA Insured      
  Water and Sewer - 11.3% (7.6% of Total Investments)      
1,185  Manteca Financing Authority, California, Sewerage Revenue Bonds, Series 2003B, 5.000%, 12/01/33 - 12/13 at 100.00  Aaa  1,194,089 
  MBIA Insured      
  San Diego Public Facilities Financing Authority, California, Subordinate Lien Water Revenue Bonds,      
  Series 2002:      
3,000  5.000%, 8/01/22 - MBIA Insured 8/12 at 100.00  AAA  3,142,080 
2,500  5.000%, 8/01/23 - MBIA Insured 8/12 at 100.00  AAA  2,612,325 
1,180  South Feather Water and Power Agency, California, Water Revenue Certificates of Participation, 4/13 at 100.00  BBB  1,210,090 
  Solar Photovoltaic Project, Series 2003, 5.375%, 4/01/24      
1,600  Sunnyvale Financing Authority, California, Water and Wastewater Revenue Bonds, Series 2001, 10/11 at 100.00  AAA  1,645,936 
  5.000%, 10/01/26 - AMBAC Insured      
$ 123,555  Total Long-Term Investments (cost $124,317,340) - 148.5%     128,822,087 
  Other Assets Less Liabilities - 3.4%     2,898,413 
Preferred Shares, at Liquidation Value - (51.9)%  (45,000,000)
   
Net Assets Applicable to Common Shares - 100%  $ 86,720,500

Forward Swaps outstanding at November 30, 2005:

    Fixed Rate   Fixed Rate  Floating Rate  Floating Rate      Unrealized 
  Notional  Paid by the Fund   Payment  Received by the Fund  Payment  Effective   Termination  Appreciation 
Counterparty  Amount  (annualized)   Frequency  Based On  Frequency    Date(2)   Date  (Depreciation) 
Citigroup  $ 1,900,000  4.699%   Semi-annually  3-month USD-LIBOR  Quarterly  2/27/06   2/27/26  $ 122,180 
JPMorgan  1,700,000  4.833%   Semi-annually  3-month USD-LIBOR    Quarterly  2/09/06   2/09/36  106,558 
Morgan Stanley  2,400,000  4.816%   Semi-annually  3-month USD-LIBOR  Quarterly  2/15/06   2/15/36  157,461 
                $ 386,199 

USD-LIBOR (United States Dollar-London Inter-Bank Offered Rates)

At least 80% of the Fund’s net assets (including net assets attributable to Preferred shares) are invested in municipal securities that are either covered by Original Issue Insurance, Secondary Market Insurance or Portfolio Insurance which ensures the timely payment of principal and interest. Up to 20% of the Fund’s net assets (including net assets attributable to Preferred shares) may be invested in municipal securities that are (i) either backed by an escrow or trust containing sufficient U.S. Government or U.S. Government agency securities (also ensuring the timely payment of principal and interest), or (ii) rated, at the time of investment, within the four highest grades (Baa or BBB or better by Moody’s, S&P or Fitch) or unrated but judged to be of comparable quality by the Adviser.

(1)    All percentages shown in the Portfolio of Investments are based on net assets applicable to Common shares unless otherwise noted.
 
(2) Effective date represents the date on which both the Fund and counterparty commence interest payment accruals on each forward swap contract.
 
* Optional Call Provisions: Dates (month and year) and prices of the earliest optional call or redemption. There may be other call provisions at varying prices at later dates. Certain mortgage-backed securities may be subject to periodic principal paydowns.
 
** Ratings: Using the higher of Standard & Poor's or Moody's rating.
 
*** Securities are backed by an escrow or trust containing sufficient U.S. Government or U.S. Government agency securities which ensures the timely payment of principal and interest. Such securities are normally considered to be equivalent to AAA rated securities.
 

Income Tax Information

The following information is presented on an income tax basis. Differences between amounts for financial statement and federal income tax purposes are primarily due to timing differences in recognizing taxable market discount and timing differences in recognizing certain gains and losses on investment transactions.

At November 30, 2005, the cost of investments was $125,282,461.

Gross unrealized appreciation and gross unrealized depreciation of investments at November 30, 2005, were as follows:

Gross unrealized:   
 Appreciation  $ 4,625,799  
 Depreciation  (1,086,173 ) 
Net unrealized appreciation (depreciation) of investments  $ 3,539,626  

Item 2. Controls and Procedures.

  1. The registrant's principal executive and principal financial officers, or persons performing similar functions, have concluded that the registrant's disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended (the "1940 Act") (17 CFR 270.30a-3(c))) are effective, as of a date within 90 days of the filing date of this report that includes the disclosure required by this paragraph, based on their evaluation of the controls and procedures required by Rule 30a-3(b) under the 1940 Act (17 CFR 270.30a-3(b)) and Rule 13a-15(b) or 15d-15(b) under the Securities Exchange Act of 1934 (17 CFR 240.13a-15(b) or 240.15d-15(b)).
  2. There were no changes in the registrant's internal control over financial reporting (as defined in Rule 30a-3(d) under the 1940 Act (17 CFR 270.30a-3(d)) that occurred during the registrant's last fiscal quarter that have materially affected, or are reasonably likely to materially affect, the registrant's internal control over financial reporting.

Item 3. Exhibits.

File as exhibits as part of this Form a separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the 1940 Act (17 CFR 270.30a-2(a)), exactly as set forth below: EX-99 CERT Attached hereto.


SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

(Registrant)         Nuveen Insured California Tax-Free Advantage Municipal Fund        

By (Signature and Title)*          /s/ Jessica R. Droeger                     
                                                    Jessica R. Droeger
                                                    Vice President and Secretary

Date         1/27/06        

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By (Signature and Title)*         /s/ Gifford R. Zimmerman                    
                                                   Gifford R. Zimmerman
                                                   Chief Administrative Officer (principal executive officer) 

Date         1/27/06        

By (Signature and Title)*         /s/ Stephen D. Foy                              
                                                   Stephen D. Foy
                                                   Vice President and Controller (principal financial officer) 

Date         1/27/06        

* Print the name and title of each signing officer under his or her signature.