Evidence is reviewed demonstrating the high level of drug and alcohol abuse and marital disharmony among physicians and the particularly high rate among anaesthetists. The relationship between these factors and the effects of fatigue is explored. The current evidence for reduction in physician performance and vigilance resulting from fatigue and sleep loss is reviewed. Supplementary indirect evidence is surveyed which suggests that increased experience may not compensate adequately for this reduced performance. Since hours of work can be controlled, it is essential that anaesthetists, their professional organizations and regulatory agencies ensure that pressure for efficiency does not result in fatigue and the consequent compromise of both patient and physician health and safety.