The epidemiology of eating disorders holds important clues for understanding factors that may contribute to their etiology. In addition, epidemiological findings speak to the public health significance of these deleterious syndromes. Information on course and outcome are important for clinicians to understand the prognosis associated with different disorders of eating and for treatment planning. This chapter reviews information on the epidemiology and course of anorexia nervosa, bulimia nervosa, and two forms of eating disorder not otherwise specified, binge eating disorder and purging disorder.