Arrowhead Research to Present at the Roth Capital Partners 23rd Annual OC Growth Stock Conference on March 16

PASADENA, Calif. — March 8, 2011 — Arrowhead Research Corporation (NASDAQ: ARWR), a nanomedicine company with development programs in oncology, obesity, and regenerative medicine, today announced that Dr. Christopher Anzalone, Chief Executive Officer, will present at the Roth 23^rd Annual OC Growth Stock Conference at 11:30 a.m. Pacific time on Wednesday, March 16, 2011. The conference is being held at the Ritz Carlton in Laguna Niguel, California.

Investors attending the conference are encouraged to schedule a one-on-one meeting at the conference with Arrowhead’s CEO Dr. Christopher Anzalone by contacting conference@roth.com, or Brandi Floberg at arrowres@tpg-ir.com or 212-481-2050.

The presentation will be webcast live and can be accessed by visiting the Company’s website at www.arrowheadresearch.com. A replay of the presentation will be archived on the Arrowhead website for 90 days.

About Arrowhead Research Corporation

Arrowhead Research Corporation (NASDAQ: ARWR) is a nanomedicine company developing innovative therapeutic products at the interface of biology and nanoengineering to cure disease and improve human health. Arrowhead addresses its target markets through focused subsidiaries, which include: Calando Pharmaceuticals, a leader in delivering small RNAs for gene silencing; Ablaris Therapeutics, an anti-obesity therapeutics company; and Nanotope, a regenerative medicine company. For more information please visit http://www.arrowheadresearch.com.