Shoulder belt use among late night bar patrons in southeastern New York was observed during May–July of 1985, approximately six months after the effective date of New York's mandatory seat belt use law. About 25 percent of the drivers observed entering and leaving bar parking lots were wearing shoulder belts compared with 36 percent of other drivers observed at nearby locations during the same night hours; during daylight hours at the nearby locations, 43 percent of drivers wore shoulder belts. The lower belt use by bar patrons was apparently not attributable to impaired judgment caused by alcohol consumption because belt use was similar when entering and leaving the bar. Bar patrons were more likely than other drivers to have driving records with crashes and/or convictions. Their failure to comply with seat belt use law to the same extent as populations with lower crash risks reduces the law's potential effectiveness. It is possible that special seat belt law enforcement efforts during night hours could increase the belt use of this high crash-risk population and, at the same time, provide an opportunity for police to screen for alcohol impairment.