Patients with anorexia nervosa (AN) frequently complain of insomnia and poor sleep quality. Some studies report changes in sleep self-reports andin several polysomnography parameters. These studies suggest that patients with AN and concomitant sleep disturbances have a poorer qualityof life, are more predisposed to the appearance of comorbidities and have a poor prognosis of AN. The presence of sleep problems appears toinfluence the course and prognosis of AN. This article intends to briefly discuss the possible impact of sleep disturbances in AN and describepotential pathophysiological mechanisms involved.