The present study examines the validity of severity diagnostic criteria for bulimia nervosa. The sample included 87 subjects. The participants were classified into 1 of 3 groups according to the Mental Disorders-IV criteria: bulimia nervosa (n = 20), sub-threshold bulimia (n = 37), and non-eating disorder (n = 30). The groups were compared regarding perceived pressure to be thin, concerns about bodshape, dietary restraint, several measures of eating and weight-related habits and attitudes, depressive symptoms, anxiety, self-esteem, social difficulties, obsessiveness, and impulsivity. Bulimics and sub-clinical bulimics differed from controls in most constructs. Few differences were found between sub-threshold and full-syndrome, raising questions about the diagnostic validity of the frequency threshold. Further evaluation of the severity criterion specified for bulimia nervosa is needed.