In a case-control study of the epidemiology of acute herniated lumbar intervertebral disc in the New Haven, Connecticut, area, it was found that driving of motor vehicles was associated with an increased risk for developing this disease. It was estimated that men who spend half or more of their time on their job driving a motor vehicle are about three times as likely to develop an acute herniated lumbar disc as those who do not hold such jobs. Persons of either sex who said that they drove a car (either away from work or at work) were more likely to develop an acute herniated lumbar disc than those who did not drive at all. These associations between driving and acute herniated lumbar disc could not be attributed to any confounding variables considered in this study.