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         811-6623         

        Nuveen California Select Tax-Free Income Portfolio         
(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:            03/31          

Date of reporting period:         12/31/07         

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 California Select Tax-Free Income Portfolio (NXC)             
    December 31, 2007             
Principal        Optional Call         
Amount (000)    Description (1)    Provisions (2)    Ratings (3)    Value 
    Consumer Staples – 4.8%             
$            220    California County Tobacco Securitization Agency, Tobacco Settlement Asset-Backed Bonds, Sonoma    6/15 at 100.00    BBB   $   204,433 
     County Tobacco Securitization Corporation, Series 2005, 4.250%, 6/01/21             
1,505    California County Tobacco Securitization Agency, Tobacco Settlement Asset-Backed Revenue    6/12 at 100.00    BBB    1,482,079 
     Bonds, Fresno County Tobacco Funding Corporation, Series 2002, 5.625%, 6/01/23             
4,045    Golden State Tobacco Securitization Corporation, California, Enhanced Tobacco Settlement    6/22 at 100.00    BBB    2,616,063 
     Asset-Backed Bonds, Series 2007A-2, 0.000%, 6/01/37             
5,770    Total Consumer Staples            4,302,575 
    Education and Civic Organizations – 10.5%             
1,000    California Educational Facilities Authority, Revenue Bonds, Stanford University, Series 1999P,    12/09 at 101.00    AAA    1,033,700 
     5.000%, 12/01/23             
45    California Educational Facilities Authority, Revenue Bonds, University of Redlands, Series    10/15 at 100.00    A3    44,201 
     2005A, 5.000%, 10/01/35             
1,000    California Educational Facilities Authority, Revenue Bonds, University of San Diego, Series    10/12 at 100.00    A2    1,044,790 
     2002A, 5.500%, 10/01/32             
    California Educational Facilities Authority, Revenue Bonds, University of the Pacific, Series 2006:             
35     5.000%, 11/01/21    11/15 at 100.00    A2    36,342 
45     5.000%, 11/01/25    11/15 at 100.00    A2    45,918 
3,000    California Infrastructure Economic Development Bank, Revenue Bonds, J. David Gladstone    10/11 at 101.00    A–    3,138,210 
     Institutes, Series 2001, 5.500%, 10/01/19             
2,000    California State Public Works Board, Lease Revenue Bonds, University of California, UCLA    10/12 at 100.00    AAA    2,075,540 
     Replacement Hospital Project, Series 2002A, 5.000%, 10/01/22 – FSA Insured             
1,000    Long Beach Bond Financing Authority, California, Lease Revenue Refunding Bonds, Long Beach    11/11 at 101.00    AAA    1,038,130 
     Aquarium of the South Pacific, Series 2001, 5.250%, 11/01/30 – AMBAC Insured             
1,000    University of California, General Revenue Bonds, Series 2006J, 4.500%, 5/15/35 – FSA Insured    5/15 at 101.00    AAA    986,770 
9,125    Total Education and Civic Organizations            9,443,601 
    Health Care – 13.5%             
445    California Health Facilities Financing Authority, Revenue Bonds, Cedars-Sinai Medical Center,    11/15 at 100.00    A2    438,183 
     Series 2005, 5.000%, 11/15/34             
110    California Health Facilities Financing Authority, Revenue Bonds, Kaiser Permanante System,    4/16 at 100.00    A+    106,864 
     Series 2006, 5.000%, 4/01/37             
2,550    California Health Facilities Financing Authority, Revenue Bonds, Sutter Health Series 2007A,    11/16 at 100.00    AA–    2,586,134 
     5.250%, 11/15/46 (UB)             
2,000    California Infrastructure Economic Development Bank, Revenue Bonds, Kaiser Hospital Assistance    8/11 at 102.00    A+    2,040,620 
     LLC, Series 2001A, 5.550%, 8/01/31             
1,500    California Statewide Community Development Authority, Hospital Revenue Bonds, Monterey    6/13 at 100.00    AAA    1,596,540 
     Peninsula Hospital, Series 2003B, 5.250%, 6/01/18 – FSA Insured             
1,500    California Statewide Community Development Authority, Insured Mortgage Hospital Revenue    11/09 at 102.00    A+    1,539,000 
     Bonds, Mission Community Hospital, Series 2001, 5.375%, 11/01/26             
1,515    California Statewide Community Development Authority, Revenue Bonds, Kaiser Permanante    3/16 at 100.00    A+    1,455,688 
     System, Series 2006, 5.000%, 3/01/41             
545    California Statewide Community Development Authority, Revenue Bonds, Kaiser Permanente    8/16 at 100.00    A+    549,469 
     System, Series 2001C, 5.250%, 8/01/31             
1,880    California Statewide Community Development Authority, Revenue Bonds, Los Angeles Orthopaedic    6/08 at 100.50    AAA    1,902,278 
     Hospital Foundation, Series 2000, 5.500%, 6/01/17 – AMBAC Insured             
12,045    Total Health Care            12,214,776 
    Housing/Multifamily – 0.8%             
750    California Statewide Community Development Authority, Student Housing Revenue Bonds, EAH –    8/12 at 100.00    CCC    727,658 
     Irvine East Campus Apartments, LLC Project, Series 2002A, 5.500%, 8/01/22 – ACA Insured             
    Housing/Single Family – 0.1%             
145    California Housing Finance Agency, Home Mortgage Revenue Bonds, Series 2006H, 5.750%,    2/16 at 100.00    AAA    154,563 
     8/01/30 – FGIC Insured (Alternative Minimum Tax)             
    Industrials – 2.0%             
1,250    California Pollution Control Financing Authority, Solid Waste Disposal Revenue Bonds, Republic    No Opt. Call    BBB+    1,297,013 
     Services Inc., Series 2002C, 5.250%, 6/01/23 (Mandatory put 12/01/17) (Alternative Minimum Tax)             
500    California Pollution Control Financing Authority, Solid Waste Disposal Revenue Bonds, Waste    1/16 at 102.00    BBB    483,625 
     Management Inc., Series 2002A, 5.000%, 1/01/22 (Alternative Minimum Tax)             
1,750    Total Industrials            1,780,638 
    Long-Term Care – 2.8%             
1,500    ABAG Finance Authority for Non-Profit Corporations, California, Insured Senior Living Revenue    11/12 at 100.00    A+    1,549,050 
     Bonds, Odd Fellows Home of California, Series 2003A, 5.200%, 11/15/22             
1,000    California Statewide Communities Development Authority, Revenue Bonds, Inland Regional Center    12/17 at 100.00    Baa1    971,690 
     Project, Series 2007, 5.250%, 12/01/27             
2,500    Total Long-Term Care            2,520,740 
    Tax Obligation/General – 22.1%             
500    California, General Obligation Bonds, Series 2003, 5.250%, 11/01/19 – RAAI Insured    11/13 at 100.00    AA    533,410 
    California, General Obligation Bonds, Series 2004:             
750     5.000%, 2/01/23    2/14 at 100.00    A+    769,133 
800     5.125%, 4/01/25    4/14 at 100.00    A+    821,000 
1,000    Fremont Unified School District, Alameda County, California, General Obligation Bonds, Series    8/12 at 101.00    AAA    1,062,980 
     2002A, 5.000%, 8/01/21 – FGIC Insured             
    Golden West Schools Financing Authority, California, General Obligation Revenue Refunding             
    Bonds, School District Program, Series 1999A:             
4,650     0.000%, 8/01/16 – MBIA Insured    No Opt. Call    AAA    3,271,182 
1,750     0.000%, 2/01/17 – MBIA Insured    No Opt. Call    AAA    1,194,375 
2,375     0.000%, 8/01/17 – MBIA Insured    No Opt. Call    AAA    1,587,213 
2,345     0.000%, 2/01/18 – MBIA Insured    No Opt. Call    AAA    1,516,465 
    Mountain View-Los Altos Union High School District, Santa Clara County, California, General             
    Obligation Capital Appreciation Bonds, Series 1995C:             
1,015     0.000%, 5/01/17 – MBIA Insured    No Opt. Call    AAA    685,490 
1,080     0.000%, 5/01/18 – MBIA Insured    No Opt. Call    AAA    690,908 
100    Roseville Joint Union High School District, Placer County, California, General Obligation    8/15 at 100.00    AAA    104,321 
     Bonds, Series 2006B, 5.000%, 8/01/27 – FGIC Insured             
3,220    Sacramento City Unified School District, Sacramento County, California, General Obligation    7/15 at 100.00    Aaa    3,366,349 
     Bonds, Series 2005, 5.000%, 7/01/27 – MBIA Insured             
1,500    San Diego Unified School District, San Diego County, California, General Obligation Bonds,    7/13 at 101.00    AAA    1,650,210 
     Series 2003E, 5.250%, 7/01/24 – FSA Insured             
2,565    Sunnyvale School District, Santa Clara County, California, General Obligation Bonds, Series    9/15 at 100.00    AAA    2,690,454 
     2005A, 5.000%, 9/01/26 – FSA Insured             
23,650    Total Tax Obligation/General            19,943,490 
    Tax Obligation/Limited – 19.5%             
1,000    Bell Community Redevelopment Agency, California, Tax Allocation Bonds, Bell Project Area,    10/13 at 100.00    AA    1,020,300 
     Series 2003, 5.625%, 10/01/33 – RAAI Insured             
3,500    California State Public Works Board, Lease Revenue Bonds, Department of Corrections,    No Opt. Call    AAA    4,108,366 
     Calipatria State Prison, Series 1991A, 6.500%, 9/01/17 – MBIA Insured             
1,000    California State Public Works Board, Lease Revenue Bonds, Department of Mental Health,    6/14 at 100.00    A    1,077,900 
     Coalinga State Hospital, Series 2004A, 5.500%, 6/01/23             
660    California, Economic Recovery Revenue Bonds, Series 2004A, 5.000%, 7/01/15    7/14 at 100.00    AA+    716,912 
120    Capistrano Unified School District, Orange County, California, Special Tax Bonds, Community    9/15 at 100.00    AAA    123,808 
     Facilities District, Series 2005, 5.000%, 9/01/24 – FGIC Insured             
360    Chino Redevelopment Agency, California, Merged Chino Redevelopment Project Area Tax Allocation    9/16 at 101.00    AAA    368,712 
     Bonds, Series 2006, 5.000%, 9/01/38 – AMBAC Insured             
1,000    Fontana Public Financing Authority, California, Tax Allocation Revenue Bonds, North Fontana    10/15 at 100.00    AAA    1,021,700 
     Redevelopment Project, Series 2005A, 5.000%, 10/01/32 – AMBAC Insured             
1,050    Golden State Tobacco Securitization Corporation, California, Enhanced Asset Backed Settlement    6/15 at 100.00    AAA    1,070,244 
     Revenue Bonds, Series 2005A, Residual Series 1500, 7.510%, 6/01/45 – AMBAC Insured (IF)             
    Irvine, California, Unified School District, Community Facilities District Special Tax Bonds,             
    Series 2006A:             
60     5.000%, 9/01/26    9/16 at 100.00    N/R    56,622 
135     5.125%, 9/01/36    9/16 at 100.00    N/R    125,618 
215    Los Angeles Community Redevelopment Agency, California, Lease Revenue Bonds, Manchester    9/15 at 100.00    Aaa    218,337 
     Social Services Project, Series 2005, 5.000%, 9/01/37 – AMBAC Insured             
1,300    Orange County, California, Special Tax Bonds, Community Facilities District 03-1 of Ladera    8/12 at 101.00    N/R    1,298,128 
     Ranch, Series 2004A, 5.625%, 8/15/34             
105    Rialto Redevelopment Agency, California, Tax Allocation Bonds, Merged Project Area, Series    9/15 at 100.00    AAA    106,226 
     2005A, 5.000%, 9/01/35 – XLCA Insured             
130    Roseville, California, Certificates of Participation, Public Facilities, Series 2003A, 5.000%,    8/13 at 100.00    AAA    133,076 
     8/01/25 – AMBAC Insured             
605    Sacramento City Financing Authority, California, Lease Revenue Refunding Bonds, Series 1993A,    No Opt. Call    AAA    682,972 
     5.400%, 11/01/20 – MBIA Insured             
3,000    San Mateo County Transit District, California, Sales Tax Revenue Bonds, Series 2005A, 5.000%,    6/15 at 100.00    AAA    3,189,810 
     6/01/21 – MBIA Insured             
225    San Mateo Union High School District, San Mateo County, California, Certificates of    12/17 at 100.00    AAA    228,791 
     Participation, Phase 1, Series 2007A, 5.000%, 12/15/30 – AMBAC Insured             
1,000    Santa Clara County Board of Education, California, Certificates of Participation, Series 2002,    4/12 at 101.00    AAA    1,039,670 
     5.000%, 4/01/25 – MBIA Insured             
1,000    Travis Unified School District, Solano County, California, Certificates of Participation,    9/16 at 100.00    Aaa    1,032,230 
     Series 2006, 5.000%, 9/01/26 – FGIC Insured             
16,465    Total Tax Obligation/Limited            17,619,422 
    Transportation – 5.3%             
1,150    Foothill/Eastern Transportation Corridor Agency, California, Toll Road Revenue Bonds, Series    1/10 at 100.00    BBB–    1,032,608 
     1995A, 5.000%, 1/01/35             
3,500    Los Angeles Harbors Department, California, Revenue Refunding Bonds, Series 2001B, 5.500%,    8/11 at 100.00    AAA    3,728,865 
     8/01/17 – AMBAC Insured (Alternative Minimum Tax)             
4,650    Total Transportation            4,761,473 
    U.S. Guaranteed – 14.8% (4)             
400    Beverly Hills Unified School District, Los Angeles County, California, General Obligation    8/12 at 100.00    AA (4)    430,900 
     Bonds, Series 2002A, 5.000%, 8/01/26 (Pre-refunded 8/01/12)             
    California Department of Water Resources, Power Supply Revenue Bonds, Series 2002A:             
2,000     5.750%, 5/01/17 (Pre-refunded 5/01/12)    5/12 at 101.00    Aaa    2,224,320 
2,000     5.125%, 5/01/19 (Pre-refunded 5/01/12)    5/12 at 101.00    Aaa    2,174,100 
2,600    California Educational Facilities Authority, Revenue Bonds, University of the Pacific, Series    11/11 at 100.00    A2 (4)    2,797,054 
     2002, 5.250%, 11/01/21 (Pre-refunded 11/01/11)             
800    California, General Obligation Bonds, Series 2004, 5.125%, 2/01/27 (Pre-refunded 2/01/14)    2/14 at 100.00    A+ (4)    877,776 
1,400    Golden State Tobacco Securitization Corporation, California, Enhanced Tobacco Settlement    6/13 at 100.00    AAA    1,541,890 
     Asset-Backed Bonds, Series 2003B, 5.500%, 6/01/33 (Pre-refunded 6/01/13)             
2,000    North Orange County Community College District, California, General Obligation Bonds, Series    8/12 at 101.00    AAA    2,170,020 
     2002A, 5.000%, 8/01/22 (Pre-refunded 8/01/12) – MBIA Insured             
1,000    Port of Oakland, California, Revenue Bonds, Series 2002M, 5.250%, 11/01/20 (Pre-refunded    11/12 at 100.00    AAA    1,092,250 
     11/01/12) – FGIC Insured             
12,200    Total U.S. Guaranteed            13,308,310 
    Utilities – 2.4%             
645    Long Beach Bond Finance Authority, California, Natural Gas Purchase Revenue Bonds, Series    No Opt. Call    A+    644,484 
     2007A, 5.500%, 11/15/37             
200    Los Angeles Department of Water and Power, California, Power System Revenue Bonds, Series    7/13 at 100.00    AAA    212,066 
     2003A-2, 5.000%, 7/01/21 – MBIA Insured             
215    Merced Irrigation District, California, Electric System Revenue Bonds, Series 2005, 5.125%,    9/15 at 100.00    AAA    220,463 
     9/01/31 – XLCA Insured             
1,010    Turlock Irrigation District, California, Revenue Refunding Bonds, Series 1992A, 6.250%,    No Opt. Call    Aaa    1,068,257 
     1/01/12 – MBIA Insured             
2,070    Total Utilities            2,145,270 
    Water and Sewer – 2.5%             
150    Healdsburg Public Financing Authority, California, Wastewater Revenue Bonds, Series 2006,    4/16 at 100.00    AAA    155,478 
     5.000%, 4/01/36 – MBIA Insured             
250    Sacramento County Sanitation District Financing Authority, California, Revenue Bonds, Series    6/16 at 100.00    AAA    260,895 
     2006, 5.000%, 12/01/31 – FGIC Insured             
825    South Feather Water and Power Agency, California, Water Revenue Certificates of Participation,    4/13 at 100.00    BBB    840,205 
     Solar Photovoltaic Project, Series 2003, 5.375%, 4/01/24             
1,000    Woodbridge Irrigation District, California, Certificates of Participation, Water Systems    7/13 at 100.00    BBB+    1,006,810 
     Project, Series 2003, 5.625%, 7/01/43             
2,225    Total Water and Sewer            2,263,388 
$        93,345    Total Investments (cost $88,070,170) – 101.1%            91,185,904 
    Floating Rate Obligations – (1.9)%            (1,700,000) 
    Other Assets Less Liabilities – 0.8%            733,670 
    Net Assets – 100%           $   90,219,574 

    The Fund may invest in “zero coupon” securities. A zero coupon security does not pay a regular interest 
    coupon to its holders during the life of the security. Tax-exempt income to the holder of the security 
    comes from accretion of the difference between the original purchase price of the security at issuance 
    and the par value of the security at maturity and is effectively paid at maturity. Such securities are 
    included in the Portfolio of Investments with a 0.000% coupon rate in their description. The market 
    prices of zero coupon securities generally are more volatile than the market prices of securities that 
    pay interest periodically. 
(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 AAA ratings shown in the Portfolio of Investments reflect the AAA ratings on certain bonds insured 
    by AMBAC, FGIC, XCLA or MBIA and/or the A ratings on certain bonds insured by ACA as of December 31, 
    2007. During December 2007, at least one rating agency reduced the rating for ACA bonds to CCC. 
    Subsequent to December 31, 2007, at least one rating agency reduced the rating for AMBAC-insured 
    bonds to AA, the rating for XCLA-insured bonds to A and the rating for FGIC-insured bonds to A3. One or 
    more rating agencies have placed each of these insurers on “negative credit watch”, which may presage 
    one or more rating reductions for such insurer or insurers in the future. If one or more insurers’ ratings are 
    reduced below AAA (or A in the case of ACA) by these rating agencies, it would likely reduce the effective 
    rating of many of the bonds insured by that insurer or insurers. 
(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. 
N/R    Not rated. 
(IF)    Inverse floating rate investment. 
(UB)    Underlying bond of an inverse floating rate trust reflected as a financing transaction pursuant to the 
    provisions of SFAS No. 140. 

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 the treatment of paydown gains and losses, 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 December 31, 2007, the cost of investments was $86,367,654.

Gross unrealized appreciation and gross unrealized depreciation of investments at December 31, 2007, were as follows:
Gross unrealized:     
  Appreciation    $3,908,294 
  Depreciation    (790,044) 
Net unrealized appreciation (depreciation) of investments    $3,118,250 

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 California Select Tax-Free Income Portfolio         

By (Signature and Title)*          /s/ Kevin J. McCarthy                    
                                                    Kevin J. McCarthy
                                                    Vice President and Secretary

Date         February 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         February 29, 2008        

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

Date        February 29, 2008        

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