Within the Department of Health and Human Services (HHS), the Food and Drug Administration (FDA) is responsible for reviewing the safety and effectiveness of medical devices. The decision to label a device as single-use or reusable rests with the manufacturer. To market a reusable device, a manufacturer must provide data demonstrating to FDA's satisfaction that the device can be cleaned and sterilized without impairing its function. Alternatively, a single-use device (SUD) may be marketed without such data after demonstrating to FDA that the device is safe and effective if used once. Even though labeled for single-use, some SUDs are reprocessed for reuse with FDA clearance. This report addresses (1) the SUD reprocessing industry--the number of reprocessing establishments, the types of devices reprocessed, and the extent to which hospitals use reprocessed SUDs, (2) the steps FDA has taken to strengthen oversight of reprocessed SUDs, both on its own and in response to legislative requirements, and (3) the safety of reprocessed SUDs compared with other types of medical devices. GAO reviewed FDA data on reprocessors, reprocessed SUDs, and device-related adverse events, as well as FDA documents and inspection reports, studies published in peer-reviewed journals, and relevant statutes and regulations. GAO interviewed FDA officials and officials from associations of manufacturers, reprocessors, and providers.