<DOCUMENT>
<TYPE>EX-99.906CERT
<SEQUENCE>3
<FILENAME>p17981exv99w906cert.txt
<DESCRIPTION>EX-99.906CERT
<TEXT>
<PAGE>

                                                              EXHIBIT 99.906CERT

  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 27, 2010                /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 27, 2010                /s/ R. Eric Chadwick
                                   ---------------------------------------------
                                   R. Eric Chadwick, Chief Financial Officer,
                                   Treasurer and Vice President
                                   (principal financial officer)
</TEXT>
</DOCUMENT>
