Fitness to drive was examined among 78 individuals with multiple sclerosis (MS) who participated with a knowledgeable informant. Illness severity, neuropsychological functioning, and external social influences each made unique contributions to the prediction of driving status. Among drivers, perceptions of social influences against driving accounted for the most variance in miles driven, whereas social influences, informants' perceptions of the patients' fitness to drive, and illness severity accounted for the most variance in adverse driving incidents. Importantly, awareness of deficit moderated fitness to drive: Drivers who were unaware of their deficits perceived less need to engage in compensatory behaviors; moreover, as perceived need to compensate decreased, miles driven and driving incidents increased. The findings have implications for interventions with persons with MS who drive.