The Anorectic Behavior Observation Scale (ABOS) is a new self-reporting questionnaire developed to obtain information from parents about specific behaviors and attitudes in their children that might be symptomatic for anorexia or bulimia nervosa. Parents of 191 eating disorder patients and 174 female students completed the questionnaire. Using a cut-off score of 19, the ABOS has a sensitivity of 90.0% and a specificity of 89.6%. A comparison with a clinician's evaluation of the patients' behavior and, in the control group, with the subjects' own judgement, revealed that parents generally give reliable information. The ABOS may be used as a valuable supplement to existing screening instruments for eating disorders.