The link between lack of sleep and subsequent medical errors served as an impetus for physician duty-hours reform. In trainee physicians, sleep loss is associated with attentional failures, but little is known about the relationship between attending physician performance and sleep loss. This retrospective cohort study examined outcomes of elective surgical procedures among attending surgeons who had worked after midnight on the previous night versus those who had not. The investigators found no differences in mortality, complications, or readmissions between procedures performed by surgeons with sleep loss compared to those without sleep loss, mirroring results of an earlier simulation study. This may be due to greater technical skill among attending surgeons, or the ability to cancel or postpone elective procedures as needed at times of fatigue. This study included many institutions, physicians, and procedure types, suggesting that short-term sleep deprivation might not be a high-yield safety target for attending surgeons.