<SEC-DOCUMENT>0001387131-18-000294-index.html : 20180129
<SEC-HEADER>0001387131-18-000294.hdr.sgml : 20180129
<ACCEPTANCE-DATETIME>20180129150430
ACCESSION NUMBER:		0001387131-18-000294
CONFORMED SUBMISSION TYPE:	N-CSR
PUBLIC DOCUMENT COUNT:		10
CONFORMED PERIOD OF REPORT:	20171130
FILED AS OF DATE:		20180129
DATE AS OF CHANGE:		20180129
EFFECTIVENESS DATE:		20180129

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Flaherty & Crumrine PREFERRED INCOME OPPORTUNITY FUND INC
		CENTRAL INDEX KEY:			0000882071
		IRS NUMBER:				954355600
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1130

	FILING VALUES:
		FORM TYPE:		N-CSR
		SEC ACT:		1940 Act
		SEC FILE NUMBER:	811-06495
		FILM NUMBER:		18555148

	BUSINESS ADDRESS:	
		STREET 1:		301 E COLORADO BLVD STE 720
		STREET 2:		C/O FLAHERTY & CRUMRINE INC
		CITY:			PASADENA
		STATE:			CA
		ZIP:			91101
		BUSINESS PHONE:		(626) 795-7300

	MAIL ADDRESS:	
		STREET 1:		301 COLORADO BLVD STE 720
		STREET 2:		C/O FLAHERTY & CRUMRINE INC
		CITY:			PASADENA
		STATE:			CA
		ZIP:			91101

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PREFERRED INCOME OPPORTUNITY FUND INC
		DATE OF NAME CHANGE:	19920929
</SEC-HEADER>
<DOCUMENT>
<TYPE>N-CSR
<SEQUENCE>1
<FILENAME>pfo-ncsr_113017.htm
<DESCRIPTION>CERTIFIED ANNUAL SHAREHOLDER REPORT
<TEXT>
Document 1 - file: pfo-ncsr_113017.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.CODE ETH
<SEQUENCE>2
<FILENAME>ex99-codeeth.htm
<DESCRIPTION>CODE OF ETHICS
<TEXT>
Document 2 - file: ex99-codeeth.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.CERT
<SEQUENCE>3
<FILENAME>ex99-cert.htm
<DESCRIPTION>CERTIFICATIONS
<TEXT>
Document 3 - file: ex99-cert.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.906CERT
<SEQUENCE>4
<FILENAME>ex99-906cert.htm
<DESCRIPTION>SECTION 906 CERTIFICATIONS
<TEXT>
Document 4 - file: ex99-906cert.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>5
<FILENAME>pfoncsr113017001.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 5 - file: pfoncsr113017001.jpg

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<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>6
<FILENAME>pfoncsr113017002.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 6 - file: pfoncsr113017002.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>7
<FILENAME>pfoncsr113017003.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 7 - file: pfoncsr113017003.jpg

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>8
<FILENAME>pfoncsr113017004.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 8 - file: pfoncsr113017004.jpg

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<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>9
<FILENAME>pfoncsr113017005.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 9 - file: pfoncsr113017005.jpg

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<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>10
<FILENAME>ex99-codeeth_img001.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 10 - file: ex99-codeeth_img001.jpg

</DOCUMENT>
</SEC-DOCUMENT>