As of September 2010, more than 16,000 pesticides were registered for use in the U.S., according to the Environmental Protection Agency (EPA). EPA reviews health and environmental effects data submitted by a company and may register a pesticide or, alternatively, grant a "conditional registration" for a pesticide under certain circumstances, even though some of the required data may not have been submitted or reviewed. The company must provide the missing data within a specified time. In 2010, environmental and other groups charged that EPA had overused conditional registrations and did not appear to have a reliable system to identify whether the required data had been submitted. This report examines the (1) number of conditional registrations EPA has granted and the basis for these; (2) extent to which EPA ensures that companies submit the required additional data and EPA reviews the data; and (3) views of relevant stakeholders on EPA's use of conditional registrations. Table and figure. This is a print on demand report.