To review the literature on the incidence and prevalence of eating disorders. We searched Medline using several key terms relating to epidemiology and eating disorders and we checked the reference lists of the articles that we found. Special attention has been paid to methodologic problems affecting the selection of populations under study and the identification of cases. An average prevalence rate for anorexia nervosa of 0.3% was found for young females. The prevalence rates for bulimia nervosa were 1% and 0.1% for young women and young men, respectively. The estimated prevalence of binge eating disorder is at least 1%. The incidence of anorexia nervosa is 8 cases per 100,000 population per year and the incidence of bulimia nervosa is 12 cases per 100,000 population per year. The incidence of anorexia nervosa increased over the past century, until the 1970s. Only a minority of people who meet stringent diagnostic criteria for eating disorders are seen in mental health care. Copyright 2003 by Wiley Periodicals, Inc. Int J Eat Disord 34: 383-396, 2003.