Notice of Effectiveness
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
Notice of Effectiveness
Effectiveness Date: January 7, 2010
Accession Number: 0001193125-09-260247
Submission Type: POS AM
CIK: 0000879407
Company Name: ARROWHEAD RESEARCH CORP
File Number: 333-161344