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)

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


Kevin J. McCarthy 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:         5/31/08         

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)             
    May 31, 2008             
Principal        Optional Call         
Amount (000)    Description (1)    Provisions (2)    Ratings (3)    Value 
    Consumer Staples – 4.2% (2.8% of Total Investments)             
$         6,070    Golden State Tobacco Securitization Corporation, California, Enhanced Tobacco Settlement    6/22 at 100.00    BBB   $   3,613,896 
     Asset-Backed Bonds, Series 2007A-2, 0.000%, 6/01/37             
    Health Care – 20.9% (13.8% of Total Investments)             
1,815    California Health Facilities Financing Authority, Revenue Bonds, Kaiser Permanante System,    3/16 at 100.00    A+    1,781,495 
     Series 2006, 5.250%, 3/01/45             
1,800    California Infrastructure Economic Development Bank, Revenue Bonds, Kaiser Hospital Assistance    8/11 at 102.00    A+    1,831,284 
     LLC, Series 2001A, 5.550%, 8/01/31             
4,000    California Statewide Community Development Authority, Insured Health Facility Revenue Bonds,    7/17 at 100.00    AAA    4,189,040 
     Catholic Healthcare West, Series 2008K, 5.500%, 7/01/41 – AGC Insured             
5,000    California Statewide Community Development Authority, Revenue Bonds, Kaiser Permanante System,    3/16 at 100.00    AAA    5,031,550 
     Series 2006, 5.000%, 3/01/41 – BHAC Insured             
4,060    California Statewide Community Development Authority, Revenue Bonds, Sherman Oaks Health    No Opt. Call    AAA    4,245,542 
     System, Series 1998A, 5.000%, 8/01/22 – AMBAC Insured             
662    California Statewide Communities Development Authority, Revenue Bonds, Saint Joseph Health    7/18 at 100.00    AAA    737,162 
     System, Trust 2554, 15.140%, 7/01/47 – FSA Insured (IF)             
17,337    Total Health Care            17,816,073 
    Housing/Multifamily – 1.3% (0.9% of Total Investments)             
1,165    Poway, California, Housing Revenue Bonds, Revenue Bonds, Poinsettia Mobile Home Park, Series    5/13 at 102.00    A+    1,119,355 
     2003, 5.000%, 5/01/23             
    Long-Term Care – 3.6% (2.4% of Total Investments)             
1,000    ABAG Finance Authority for Non-Profit Corporations, California, Insured Senior Living Revenue    11/12 at 100.00    A+    1,019,070 
     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+    2,025,900 
     California Retired Officers Community Corporation – Paradise Valley Estates, Series 2002,             
     5.250%, 1/01/26             
3,000    Total Long-Term Care            3,044,970 
    Tax Obligation/General – 20.0% (13.2% of Total Investments)             
2,000    Butte-Glenn Community College District, Butte and Glenn Counties, California, General    8/12 at 101.00    Aaa    2,052,960 
     Obligation Bonds, Series 2002A, 5.000%, 8/01/26 – MBIA Insured             
    California State, General Obligation Bonds, Series 2002:             
2,460     5.000%, 4/01/27 – AMBAC Insured    4/12 at 100.00    AAA    2,490,652 
55     5.250%, 4/01/30 – XLCA Insured    4/12 at 100.00    A1    56,163 
515    Fontana Unified School District, San Bernardino County, California, General Obligation Bonds,    8/18 at 100.00    AAA    662,445 
     Trust 2668, 15.350%, 8/01/28 – FSA Insured (IF)             
450    Fremont Unified School District, Alameda County, California, General Obligation Bonds, Series    8/12 at 101.00    Aa3    462,546 
     2002A, 5.000%, 8/01/25 – FGIC Insured             
2,000    Los Angeles, California, General Obligation Bonds, Series 2002A, 5.000%, 9/01/22 – MBIA Insured    9/12 at 100.00    AAA    2,080,560 
1,000    Murrieta Valley Unified School District, Riverside County, California, General Obligation    9/13 at 100.00    A1    1,026,860 
     Bonds, Series 2003A, 5.000%, 9/01/26 – FGIC Insured             
1,000    Murrieta Valley Unified School District, Riverside County, California, General Obligation    9/17 at 100.00    AAA    982,000 
     Bonds, Series 2007, 4.500%, 9/01/30 – FSA Insured             
140    Roseville Joint Union High School District, Placer County, California, General Obligation    8/15 at 100.00    AA–    144,327 
     Bonds, Series 2006B, 5.000%, 8/01/27 – FGIC Insured             
3,000    San Diego Unified School District, California, General Obligation Bonds, Election of 1998,    7/10 at 100.00    AAA    3,157,170 
     Series 2000B, 5.125%, 7/01/22 – MBIA Insured             
3,855    San Rafael City High School District, Marin County, California, General Obligation Bonds,    8/12 at 100.00    AAA    3,934,644 
     Series 2003A, 5.000%, 8/01/28 – FSA Insured             
16,475    Total Tax Obligation/General            17,050,327 
    Tax Obligation/Limited – 45.4% (30.0% of Total Investments)             
550    Baldwin Park Public Financing Authority, California, Sales Tax and Tax Allocation Bonds,    8/13 at 102.00    BBB    573,491 
     Puente Merced Redevelopment Project, Series 2003, 5.250%, 8/01/21             
1,165    Burbank Public Financing Authority, California, Revenue Refunding Bonds, Golden State    12/13 at 100.00    AAA    1,223,961 
     Redevelopment Project, Series 2003A, 5.250%, 12/01/22 – AMBAC Insured             
4,000    California State Public Works Board, Lease Revenue Bonds, Department of General Services,    12/12 at 100.00    AAA    4,043,320 
     Capital East End Project, Series 2002A, 5.000%, 12/01/27 – AMBAC Insured             
170    Capistrano Unified School District, Orange County, California, Special Tax Bonds, Community    9/15 at 100.00    Baa3    171,324 
     Facilities District, Series 2005, 5.000%, 9/01/24 – FGIC Insured             
525    Chino Redevelopment Agency, California, Merged Chino Redevelopment Project Area Tax Allocation    9/16 at 101.00    AAA    518,506 
     Bonds, Series 2006, 5.000%, 9/01/38 – AMBAC Insured             
1,610    Folsom Public Financing Authority, California, Special Tax Revenue Bonds, Series 2004A,    9/12 at 102.00    AAA    1,646,289 
     5.000%, 9/01/21 – AMBAC Insured             
1,875    Golden State Tobacco Securitization Corporation, California, Enhanced Tobacco Settlement    6/15 at 100.00    AAA    2,061,506 
     Revenue Bonds, Drivers Trust 2091, 11.873%, 6/01/45 – AGC Insured (IF)             
3,285    Golden State Tobacco Securitization Corporation, California, Tobacco Settlement Asset-Backed    6/15 at 100.00    Aaa    3,169,729 
     Revenue Bonds, Series 2005A, 5.000%, 6/01/45 – AMBAC Insured             
1,000    Hesperia Public Financing Authority, California, Redevelopment and Housing Projects Tax    9/17 at 100.00    A3    947,050 
     Allocation Bonds, Series 2007A, 5.000%, 9/01/37 – XLCA Insured             
5,540    Irvine Public Facilities and Infrastructure Authority, California, Assessment Revenue Bonds,    9/13 at 100.00    AAA    5,720,770 
     Series 2003C, 5.000%, 9/02/21 – AMBAC Insured             
315    Los Angeles Community Redevelopment Agency, California, Lease Revenue Bonds, Manchester Social    9/15 at 100.00    Aaa    314,496 
     Services Project, Series 2005, 5.000%, 9/01/37 – AMBAC Insured             
1,770    Los Angeles Unified School District, California, Certificates of Participation, Administration    10/12 at 100.00    AAA    1,784,974 
     Building Project II, Series 2002C, 5.000%, 10/01/27 – AMBAC Insured             
2,000    Los Angeles, California, Certificates of Participation, Municipal Improvement Corporation,    6/13 at 100.00    AAA    2,022,920 
     Series 2003AW, 5.000%, 6/01/33 – AMBAC Insured             
1,500    Los Angeles, California, Municipal Improvement Corporation, Lease Revenue Bonds, Police    1/17 at 100.00    AA–    1,433,880 
     Headquarters, Series 2006A, 4.750%, 1/01/31 – FGIC Insured             
1,500    Los Osos, California, Improvement Bonds, Community Services Wastewater Assessment District 1,    9/10 at 103.00    AAA    1,464,150 
     Series 2002, 5.000%, 9/02/33 – MBIA Insured             
150    Rialto Redevelopment Agency, California, Tax Allocation Bonds, Merged Project Area, Series    9/15 at 100.00    A–    149,546 
     2005A, 5.000%, 9/01/35 – XLCA Insured             
190    Roseville, California, Certificates of Participation, Public Facilities, Series 2003A, 5.000%,    8/13 at 100.00    AAA    192,839 
     8/01/25 – AMBAC 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    3,021,780 
3,300     5.000%, 2/01/32 – AMBAC Insured    2/12 at 100.00    AAA    3,309,636 
1,200    San Diego Redevelopment Agency, California, Subordinate Lien Tax Increment and Parking Revenue    9/09 at 101.00    Baa2    1,203,096 
     Bonds, Centre City Project, Series 2003B, 5.250%, 9/01/26             
2,770    San Jose Financing Authority, California, Lease Revenue Refunding Bonds, Civic Center Project,    6/12 at 100.00    AAA    2,810,082 
     Series 2002B, 5.000%, 6/01/32 – AMBAC Insured             
1,000    San Jose Redevelopment Agency, California, Tax Allocation Bonds, Merged Project Area, Series    8/15 at 100.00    AAA    1,017,410 
     2005A, 5.000%, 8/01/28 – MBIA Insured             
38,415    Total Tax Obligation/Limited            38,800,755 
    Transportation – 10.1% (6.7% of Total Investments)             
5,480    Bay Area Governments Association, California, BART SFO Extension, Airport Premium Fare Revenue    8/12 at 100.00    AAA    5,586,970 
     Bonds, Series 2002A, 5.000%, 8/01/26 – AMBAC Insured             
2,000    Foothill/Eastern Transportation Corridor Agency, California, Toll Road Revenue Bonds, Series    1/10 at 100.00    BBB–    1,698,560 
     1995A, 5.000%, 1/01/35             
1,300    San Francisco Airports Commission, California, Revenue Bonds, San Francisco International    5/10 at 101.00    A1    1,321,671 
     Airport, Second Series 2000, Issue 26B, 5.000%, 5/01/25 – FGIC Insured             
8,780    Total Transportation            8,607,201 
    U.S. Guaranteed – 24.2% (16.0% of Total Investments) (4)             
1,000    Berryessa Union School District, Santa Clara County, California, General Obligation Bonds,    8/12 at 100.00    AAA    1,083,180 
     Series 2003C, 5.000%, 8/01/21 (Pre-refunded 8/01/12) – FSA Insured             
    California State, General Obligation Bonds, Series 2002:             
1,290     5.000%, 4/01/27 (Pre-refunded 4/01/12) – AMBAC Insured    4/12 at 100.00    AAA    1,390,310 
2,945     5.250%, 4/01/30 (Pre-refunded 4/01/12) – XLCA Insured    4/12 at 100.00    A1 (4)    3,200,567 
500    California, General Obligation Bonds, Series 2004, 5.250%, 4/01/34 (Pre-refunded 4/01/14)    4/14 at 100.00    AAA    557,390 
1,625    Golden State Tobacco Securitization Corporation, California, Tobacco Settlement Asset-Backed    6/13 at 100.00    AAA    1,946,978 
     Revenue Bonds, Series 2003A-2, 7.900%, 6/01/42 (Pre-refunded 6/01/13)             
    Hacienda La Puente Unified School District, Los Angeles County, California, General Obligation             
    Bonds, Series 2003B:             
4,500     5.000%, 8/01/26 (Pre-refunded 8/01/13) – FSA Insured    8/13 at 100.00    AAA    4,926,015 
2,030     5.000%, 8/01/27 (Pre-refunded 8/01/13) – FSA Insured    8/13 at 100.00    AAA    2,222,180 
1,260    Rancho Mirage Joint Powers Financing Authority, California, Revenue Bonds, Eisenhower Medical    7/14 at 100.00    A3 (4)    1,425,299 
     Center, Series 2004, 5.875%, 7/01/26 (Pre-refunded 7/01/14)             
1,220    San Jose Redevelopment Agency, California, Tax Allocation Bonds, Merged Area Redevelopment    8/10 at 101.00    AAA    1,301,825 
     Project, Series 2002, 5.000%, 8/01/32 (Pre-refunded 8/01/10) – MBIA Insured             
2,390    Solano County, California, Certificates of Participation, Series 2002, 5.250%, 11/01/24    11/12 at 100.00    AAA    2,623,623 
     (Pre-refunded 11/01/12) – MBIA Insured             
18,760    Total U.S. Guaranteed            20,677,367 
    Utilities – 6.7% (4.4% of Total Investments)             
1,000    Anaheim Public Finance Authority, California, Second Lien Electric Distribution Revenue Bonds,    10/14 at 100.00    AAA    1,052,030 
     Series 2004, 5.250%, 10/01/21 – MBIA Insured             
945    Long Beach Bond Finance Authority, California, Natural Gas Purchase Revenue Bonds, Series    No Opt. Call    A+    918,143 
     2007A, 5.500%, 11/15/37             
3,055    Los Angeles Department of Water and Power, California, Power System Revenue Bonds, Series    7/11 at 100.00    AAA    3,196,355 
     2001A-1, 5.250%, 7/01/22 – FSA Insured             
275    Los Angeles Department of Water and Power, California, Power System Revenue Bonds, Series    7/13 at 100.00    AAA    286,314 
     2003A-2, 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    A–    310,347 
     9/01/31 – XLCA Insured             
5,585    Total Utilities            5,763,189 
    Water and Sewer – 13.6% (9.0% of Total Investments)             
1,000    Castaic Lake Water Agency, California, Certificates of Participation, Series 2006C, 5.000%,    8/16 at 100.00    AAA    1,016,020 
     8/01/36 – MBIA Insured             
750    Fortuna Public Finance Authority, California, Water Revenue Bonds, Series 2006, 5.000%,    10/16 at 100.00    AAA    772,628 
     10/01/36 – FSA Insured             
215    Healdsburg Public Financing Authority, California, Wastewater Revenue Bonds, Series 2006,    4/16 at 100.00    AAA    217,348 
     5.000%, 4/01/36 – MBIA Insured             
895    Manteca Financing Authority, California, Sewerage Revenue Bonds, Series 2003B, 5.000%,    12/13 at 100.00    Aaa    909,839 
     12/01/33 – MBIA Insured             
170    Marina Coast Water District, California, Enterprise Certificate of Participation, Series 2006,    6/16 at 100.00    AAA    170,891 
     5.000%, 6/01/31 – 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    3,107,010 
2,500     5.000%, 8/01/23 – MBIA Insured    8/12 at 100.00    AAA    2,580,750 
1,180    South Feather Water and Power Agency, California, Water Revenue Certificates of Participation,    4/13 at 100.00    BBB    1,190,147 
     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    1,628,400 
     5.000%, 10/01/26 – AMBAC Insured             
11,310    Total Water and Sewer            11,593,033 
$  126,897    Total Long-Term Investments (cost $125,873,433) – 150.0%            128,086,166 
    Short-Term Investments – 1.2% (0.8% of Total Investments)             
$      1,000    Pasadena, California, Certificates of Participation, Variable Rate Demand Obligations, City        VMIG-1    1,000,000 
     Hall and Park Improvement Projects, Series 2003, 2.750%, 2/01/33 – AMBAC Insured (5)             
    Total Short-Term Investments (cost $1,000,000)            1,000,000 
    Total Investments (cost $126,873,433) – 151.2%            129,086,166 
    Other Assets Less Liabilities – 1.5%            1,283,671 
    Preferred Shares, at Liquidation Value – (52.7)% (6)            (45,000,000)
    Net Assets Applicable to Common Shares – 100%          $  85,369,837 

    As of May 31, 2008, 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, Standard 
    & Poor’s 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)    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. 
(3)    Ratings: Using the higher of Standard & Poor’s Group (“Standard & Poor’s”) or Moody’s Investor Service, 
    Inc. (“Moody’s”) rating. Ratings below BBB by Standard & Poor’s or Baa by Moody’s are considered to 
    be below investment grade. 
    The Portfolio of Investments may reflect the ratings on certain bonds insured by ACA, AMBAC, CIFG, FGIC, 
    MBIA, RAAI and XLCA as of May 31, 2008. Subsequent to May 31, 2008, and during the period this Portfolio 
    of Investments was prepared, there may have been reductions to the ratings of certain bonds resulting from 
    changes to the ratings of the underlying insurers both during the period and after period end. Such reductions 
    would likely reduce the effective rating of many of the bonds insured by that insurer or insurers presented 
    at period end. 
(4)    Backed by an escrow or trust containing sufficient U.S. Government or U.S. Government agency securities 
    which ensure the timely payment of principal and interest. Such investments are normally considered to 
    be equivalent to AAA rated securities. 
(5)    Investment has a maturity of more than one year, but has variable rate and demand features which qualify 
    it as a short-term investment. The rate disclosed is that in effect at the end of the reporting period. This 
    rate changes periodically based on market conditions or a specified market index. 
(6)    Preferred Shares, at Liquidation Value as a percentage of total investments is (34.9)%. 
(IF)    Inverse floating rate investment. 

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, timing differences in recognizing certain gains and losses on investment transactions and the treatment of investments in inverse floating rate transactions subject to SFAS No.140. To the extent that differences arise that are permanent in nature, such amounts are reclassified within the capital accounts on the Statement of Assets and Liabilities presented in the annual report, based on their federal tax basis treatment; temporary differences do not require reclassification. Temporary and permanent differences do not impact the net asset value of the Fund.

At May 31, 2008, the cost of investments was $127,251,327.

Gross unrealized appreciation and gross unrealized depreciation of investments at May 31, 2008, were as follows:

Gross unrealized:     
  Appreciation    $  4,033,202 
  Depreciation    (2,198,363)
Net unrealized appreciation (depreciation) of investments    $  1,834,839 

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: See 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/ Kevin J. McCarthy                    
                                                  Kevin J. McCarthy
                                                  Vice President and Secretary

Date         July 29, 2008        

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         July 29, 2008        

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

Date        July 29, 2008