Considerable research has shown that sleep deprivation can affect cognitive performance, but the link between fatigue and clinical outcomes, particularly for surgeons, remains unclear. This case-control study sought to determine whether there was an association between sleep deprivation—defined as having performed an emergency procedure the night before—and complication rates for elective laparoscopic cholecystectomy. Although a prior single-institution study found increased complication rates for daytime procedures performed after operating the night before, this study used a much larger population-based database from Ontario, Canada and found no evidence of greater complications in patients whose surgeons had operated the night before. As duty hour restrictions for resident physicians appear to have had no effect on clinical outcomes, this study provides an argument against restricting practicing physician's duty hours.