Notice of Effectiveness
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
Notice of Effectiveness
Effectiveness Date: June 11, 2010
Accession Number: 0000950130-10-002693
Submission Type: POS AM
CIK: 0000879407
Company Name: ARROWHEAD RESEARCH CORP
File Number: 333-148218