Background: Motorcycle drivers have the highest frequency of alcohol use among all road users. This study examines alcohol use among a large sample of injured motorcycle drivers and examines how crash characteristics differ with the use of alcohol, Methods: Over 3000 motorcycle drivers who crashed between January 1, 1991, and December 31, 1992, were studied, All fatally injured drivers in 11 California counties and a sample of nonfatally injured drivers treated in 28 hospitals were included in the study if a crash report and medical record were available, Results: Among drivers tested for alcohol use, 42% tested positive for the presence of alcohol, Drinking drivers were more likely to be speeding and less likely to wear a helmet, and more frequency had single motorcycle crashes than nondrinking drivers, Crash characteristics, but not alcohol use, were predictive of increased injury severity, Conclusion: Alcohol use remains a significant factor in motorcycle crashes and is an important area for injury prevention efforts.