CERTIFICATION PURSUANT TO RULE 30A-2(B) UNDER THE 1940 ACT AND SECTION 906
                            OF THE SARBANES-OXLEY ACT

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

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

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

Date:    JULY 30, 2008            /S/ DONALD F. CRUMRINE
        --------------            ---------------------------------------------
                                  Donald F. Crumrine, Director, Chairman of
                                  the Board and Chief Executive Officer
                                  (principal executive officer)


I, R. Eric Chadwick, Chief Financial Officer, Treasurer and Vice President of
Flaherty & Crumrine Preferred Income Opportunity Fund Incorporated
(the "Registrant"), certify that:

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

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

Date:    JULY 30, 2008            /S/ R. ERIC CHADWICK
        --------------            ---------------------------------------------
                                  R. Eric Chadwick, Chief Financial Officer,
                                  Treasurer and Vice President
                                  (principal financial officer)