The potential for a worldwide influenza pandemic caused by bird flu has heightened public interest regarding the availability and affordability of influenza antiviral medications such as Tamiflu. As countries prepare for the possibility of a pandemic flu outbreak, orders for Tamiflu have far exceeded the production capacities of the Swiss pharmaceutical company Roche, Inc., that owns the exclusive right to manufacture the patented drug. In addition, poor countries in Asia and Africa, where any bird flu crisis could occur first, suggest that they cannot afford to stockpile supplies of Tamiflu for treating their human populations at current prices. This report identifies and analyzes the patent law aspects of the current avian influenza drug situation. First, the report explains the role that patent rights have played in affecting the availability of Tamiflu. Second, the report examines options for increasing the drug's production, including the possibility of governments abrogating Roche's patent rights by issuing compulsory licenses to other drug companies to manufacture generic versions of Tamiflu without Roche's consent. Such option is available to countries under the Trade-Related Aspects of Intellectual Property (TRIPS) Agreement, a component of the treaties that created the World Trade Organization (WTO) in 1995. The U.S. government's authority to declare compulsory licenses is Section 1498(a) of Title 28 of the U.S. Code. It is contended that such suspension of Roche's patent rights to Tamiflu are necessary to mass produce the drug to meet the enormous demand, but this proposition has been challenged. Other legal mechanisms to increase the supply of, and lower the price for, Tamiflu include voluntary licensing agreements with other pharmaceutical companies. This report will be updated as events warrant.