Twenty-five combat veterans hospitalized for treatment of posttraumatic stress disorder were evaluated for the presence of other disorders. Fourteen patients (56%) met operationally defined criteria for one additional diagnosis, five (20%) for two additional diagnoses, and two (8%) for three additional diagnoses. The coexisting syndromes included alcoholism, drug dependence, antisocial personality disorder, somatization disorder, endogenous depression, and organic mental syndrome. The authors caution that neither the stress disorder nor the coexisting syndrome should be considered the primary condition; clinicians should screen patients with stress disorders for other conditions and treat them when possible.