Concerns about body shape are common among young women in Western cultures, and, in an extreme form, they constitute a central feature of the eating disorders anorexia nervosa and bulimia nervosa. To date there has been no satisfactory measure of such concerns. A self-report instrument, the Body Shape Questionnaire (BSQ) has therefore been developed. The items that constitute this measure were derived by conducting semistructured interviews with various groups of women including patients with anorexia nervosa and bulimia nervosa. The BSQ has been administered to three samples of young women in the community as well as to a group of patients with bulimia nervosa. The concurrent and discriminant validity of the measure have been shown to be good. The BSQ provides a means of investigating the role of concerns about body shape in the development, maintenance, and treatment of anorexia nervosa and bulimia nervosa.