The ASA Guidelines for the Ethical Practice of Anesthesiology outline the ethical responsibilities of anesthesiologists. Sleep is a basic human need. Sleep deprivation has a negative impact on performance, including the special sensory capabilities mentioned in the ethical guidelines. A basic primer in sleep physiology is important to understand the issues of sleep deprivation and its effect on performance. Anesthesiologists have an ethical responsibility to be optimally prepared to safely care for patients and this includes avoidance of impairments from any cause. Fatigue has been shown to affect performance to a similar degree that is associated with legal intoxication with alcohol. Anesthesiologists have ethical obligations to each other to promote work breaks, and discourage sleep deprivation among colleagues. Anesthesiologists also have obligations to work with hospitals to promote a culture of patient safety and proactively address fatigue-related risks.