While it is known that some individuals with anorexia nervosa are characterized by compulsive overeating (bulimia), only recently have workers suggested that bulimia may be associated with distinctive personality and etiological processes. This investigation sought to evaluate the validity of distinguishing anorectics with bulimia from anorectics who maintain a continuous pattern of fasting (restricters) by examining a) the personality characteristics of the parents and b) the nature and prevalence of psychiatric morbidity in first- and second-degree relatives of 35 bulimic and 35 restricter anorectics. Based on empirical data indicating that bulimics are significantly more labile, impulsive, and susceptible to mood disturbance than their restricter counterparts, it was hypothesized that personality trait disturbances in parents and higher familial prevalence of affective and impulse disorders would distinguish this group. This was confirmed. Multivariate analyses of variance revealed fathers of bulimics scored higher than fathers of restricters on Minnesota Multiphasic Personality Inventory scales measuring impulsivity, low tolerance for frustration, dissatisfaction with familial relations, and excitability, whereas mothers of bulimics scored higher than mothers of restricters on depression, hostility, and dissatisfaction with familial relations. A multiple regression analysis showed that maternal depression and paternal impulse disturbance and depression were predictive of greater severity of bulimia in the subjects. Analysis of psychiatric interview data indicated that affective disorder was significantly more prevalent in first- and second-degree relatives of bulimics, and that the prevalence exceeded the expected rate of illness in the general population; similarly, rates of familial alcoholism and drug use disorders were significantly higher in the bulimic group. Results are discussed in terms of biological and psychological processes underlining the pathogenesis of the bulimia symptom pattern in the anorexia nervosa syndrome.