OBJECTIVES: To evaluate the association between chronic medical conditions, functional, cognitive, and visual impairments and driving difficulty and habits among older drivers. DESIGN: Cross-sectional study. SETTING: Mobile County, Alabama. PARTICIPANTS: A total of 901 residents of Mobile County, Alabama aged 65 or older who possessed a driver's license in 1996. MEASUREMENTS: Information on demographic characteristics, functional limitations, chronic medical conditions, driving habits, and visual and cognitive function were collected via telephone. The three dependent variables in this study were difficulty with driving, defined as any reported difficulty in > or = 3 driving situations (e.g. at night), low annual estimated mileage, defined as driving less than 3000 miles in 1996, and low number of days ( < or = 3) driven per week. RESULTS: A history of falls, kidney disease or stroke was associated with difficulty driving. Older drivers with a history of kidney disease were more likely to report a low annual mileage than subjects without kidney disease. Low annual mileage was also associated with cognitive impairment. In general, older drivers with a functional impairment were more likely to drive less than 4 days per week. Older drivers with a history of cataracts or high blood pressure were more likely to report a low number of days driven per week, while subjects with visual impairment were at increased risk of experiencing difficulty driving as well as low number of days driven per week. CONCLUSIONS: The results underscore the need to further understand the factors negatively affecting driving independence and mobility in older drivers, as well as the importance of improved communication between older adults and health care professionals regarding driving.