Limitations on housestaff duty hours were implemented with the intent of protecting patients by reducing errors made by fatigued residents. Indeed, prior studies have shown that sleep-deprived residents are more prone to committing errors and inadvertently sustaining needlestick injuries. However, comparatively little attention has been paid to the effect of fatigue on attending physicians. Conducted at a single academic medical center, this study evaluated the relationship between sleep deprivation (defined as having operated the night before the scheduled procedure) and complication rates for a range of surgical, obstetric, and gynecologic procedures. There was no overall link between fatigue and complications, but the complication rate was increased for surgeons who had the opportunity to sleep less than 6 hours. Other studies have found that fatigue is influenced by many factors other than hours worked, and therefore further reductions in shift length (as called for in a recent Institute of Medicine report) may not significantly improve patient safety.