OBJECTIVE The prevalence of body dysmorphic disorder in patients with anorexia nervosa is unknown. We hypothesized that body dysmorphic disorder would be underdiagnosed in patients with anorexia nervosa and that comorbidity with body dysmorphic disorder would result in greater overall dysfunction. METHODS Forty-one patients with DSM-IV anorexia nervosa completed the Body Dysmorphic Disorder Questionnaire, a self-report screen for body dysmorphic disorder. A follow-up interview was conducted using a reliable clinician-administered semistructured diagnostic instrument for DSM-IV body dysmorphic disorder. Delusionality about appearance was assessed using a validated semistructured interview. Comorbid DSM-IV diagnoses, number of hospitalizations and suicide attempts were obtained by means of a detailed diagnostic interview. RESULTS Sixteen (39%) of the 41 patients with anorexia nervosa were diagnosed with comorbid body dysmorphic disorder unrelated to weight concerns. The anorexia nervosa patients with body dysmorphic disorder had significantly lower overall functioning and higher levels of delusionality than the anorexic patients without body dysmorphic disorder. CONCLUSIONS These preliminary results suggest that body dysmorphic disorder may be relatively common among patients with anorexia nervosa. The presence of comorbid body dysmorphic disorder may indicate a more severe form of illness.