Summary: New drugs marketed in the United States must be approved first by the Food and Drug Administration (FDA). FDA grants its approval after it has determined from data submitted by a drug's sponsor that the drug is safe and effective and that the manufacturer can guarantee its quality. GAO found a considerable reduction in approval time for new drug applications between 1987 and 1992. It took an average of 33 months for new drug applications submitted in 1987 to be approved but only 19 months on average to approve new drug applications submitted in 1992. The priority that FDA assigns to a new drug application and the experience of its sponsors significantly affect the likelihood of a quick decision. FDA assigns priority status to drugs that are expected to provide therapeutic benefit to consumers beyond that of drugs already marketed. Priority status and sponsor experience are also the two factors that predict the likelihood of drug approval. Finally, the limited data available on review time for FDA and its counterpart in the United Kingdom paint a more ambiguous picture than presented in many recent reports. In fact, the latest data published by the regulatory agency in the United Kingdom show that it does not have faster approval times than FDA.