CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT

I,  Donald F.  Crumrine,  Director,  Chairman  of the Board and Chief  Executive
Officer of Preferred Income Opportunity Fund Incorporated (the "Fund"),  certify
that:

         1.     The Form N-CSR of the Fund (the  "Report")  fully  complies with
                the  requirements  of Section  13(a) or 15(d) of the  Securities
                Exchange Act of 1934; and

         2.     The information  contained in the Report fairly presents, in all
                material  respects,  the  financial  condition  and  results  of
                operations of the Fund.

Date:    JULY 30, 2003           /S/ DONALD F. CRUMRINE
     -------------------         --------------------------------------------
                                 Donald F. Crumrine, Director, Chairman of the
                                 Board and Chief Executive Officer
                                 (principal executive officer)

I, Peter C. Stimes,  Chief  Financial and Accounting  Officer,  Vice  President,
Treasurer  &  Assistant   Secretary  of  Preferred   Income   Opportunity   Fund
Incorporated (the "Fund"), certify that:

         1.     The Form N-CSR of the Fund (the  "Report")  fully  complies with
                the  requirements  of Section  13(a) or 15(d) of the  Securities
                Exchange Act of 1934; and

         2.     The information  contained in the Report fairly presents, in all
                material  respects,  the  financial  condition  and  results  of
                operations of the Fund.

Date:    JULY 30, 2003          /S/ PETER C. STIMES
     -------------------        --------------------------------------------
                                Peter C. Stimes, Chief Financial and Accounting
                                Officer, Vice President, Treasurer & Assistant
                                Secretary
                                (principal financial officer)

A signed  original of this written  statement  required by Section 906, or other
document authenticating, acknowledging, or otherwise adopting the signature that
appears in typed form within the  electronic  version of this written  statement
required  by  Section  906,  has been  provided  to the  registrant  and will be
retained  by the  registrant  and  furnished  to  the  Securities  and  Exchange
Commission or its staff upon request.