To examine the relationship between drug abuse and eating disorders in a longitudinal sample. In a prospective study, women diagnosed with either DSM-IV anorexia nervosa (n = 136) or bulimia nervosa (n = 110) were interviewed and assessed for research diagnostic criteria drug use disorder (DUD) every 6-12 months over 8.6 years. Contrary to expectation, DUD did not influence recovery from either eating disorder. Multivariate analyses indicated that alcohol use and suicide attempts over the course of the study, as well as hospitalization for an affective disorder before the study, predicted DUD in anorexia nervosa. For bulimia nervosa, multivariate predictors included the severity of alcohol use and the severity of bulimic symptoms over the course of the study, and a hospitalization before study entry for a nonaffective disorder. Drug abuse in women with eating disorders is an area of clinical concern and should be monitored routinely.