Considerable research evidence has accumulated indicating that there is an increased likelihood for illness and injury among employees working in long-hour schedules and schedules involving unconventional shift work (e.g., night and evening shifts). In addition, studies show that fatigue-related errors made by employees working in these kind of demanding schedules can have serious and adverse repercussions for public safety. As the result of these concerns, new protective legislation is being advocated in the United States, for instance, to restrict the hours of work among nurses and other health-care professionals. This article reviews the history of concerns about long working hours and the current scientific evidence regarding their effects on workers’ health. The ethical implications of unconventional shift work and long work-hour schedules are considered. Relevant ethical considerations involve mandatory or unpaid overtime and the possibility of employer coercion, the political basis for government regulation of working hours, potential limits on voluntary assumption of risk, societal benefits accruing from the equitable distribution of available working hours, gender-based inequities related to working hours, and employer responsibilities for protecting individuals who are not employees from the spillover effects of demanding work schedules.