The literature on resident performance and sleep deprivation is reviewed. It is suggested that despite the urgent need for definitive work in the area, current research is sparse and inconclusive. It also is suggested that the research that does exist implies there are potentially severe negative effects from sleep deprivation on physicians-in-training. The present authors believe that justifications for sleep-depriving night call schedules remain untested and that the presence of sleep-depriving night call as part of residency training should be reevaluated.