<SEC-DOCUMENT>0000940400-18-000103-index.html : 20180129
<SEC-HEADER>0000940400-18-000103.hdr.sgml : 20180129
<ACCEPTANCE-DATETIME>20180129154358
ACCESSION NUMBER:		0000940400-18-000103
CONFORMED SUBMISSION TYPE:	NSAR-B
PUBLIC DOCUMENT COUNT:		3
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:		NSAR-B
		SEC ACT:		1940 Act
		SEC FILE NUMBER:	811-06495
		FILM NUMBER:		18555388

	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>NSAR-B
<SEQUENCE>1
<FILENAME>pfoanwserfile.fil
<TEXT>
Document 1 - file: pfoanwserfile.fil

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.77B ACCT LTTR
<SEQUENCE>2
<FILENAME>FCNSARLetter77B.txt
<TEXT>
Document 2 - file: FCNSARLetter77B.txt

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.77Q2 ITEM 405
<SEQUENCE>3
<FILENAME>PFO77Q2.txt
<TEXT>
Document 3 - file: PFO77Q2.txt

</DOCUMENT>
</SEC-DOCUMENT>