This report examined the helmet use of motorcycle riders 21 and older involved in fatal crashes. The analysis is based on data from the National Highway Traffic Safety Administration's Fatality Analysis Reporting System (FARS) over the years 1997-2006. Crashes were separated into two categories: (a) single-vehicle motor crashes and (b) two-vehicle crashes involving one passenger vehicle and one motorcycle. A logistic regression model was constructed to perform a multivariate analysis that examined the relationship between a motorcycle rider's helmet use and many other factors.