This study compares rates of comorbidity of lifetime psychiatric disorder in a clinical sample of women with bulimia, with general population base rates, and with rates of comorbidity among bulimic women in the general population. Eighty-four per cent of the clinical sample of bulimic women had a lifetime affective disorder, and 44% a lifetime alcohol or drug disorder. These rates of disorder were significantly higher than the base rates in the general population. Bulimic women in the general population also had more affective and substance-use disorders than the general population base rates, but the rates of these disorders were lower than found in the clinical sample. In the general population, quite similar rates of other disorders including generalized anxiety, panic, phobia and obsessive–compulsive disorder, are found among those with bulimia, substance-use disorder and depression. Furthermore, among those with depression and substance-use disorder in the general population, rates of eating disorder are comparable. Rather than suggesting a specific relationship between bulimia and either depression or substance-use disorder, the data from this study suggest that the presence of any disorder is associated with a non-specific increase in the likelihood of other psychiatric disorder.