OBJECTIVES: The study replicated methods used in an earlier study to determine the prevalence of dissociative disorders among patients with substance use disorders and to examine demographic characteristics and history of childhood abuse among patients with and without dissociative comorbidity. METHODS: A total of 100 inpatients who were completing a substance abuse treatment program at a VA medical center were interviewed using the Dissociative Disorders Interview Schedule, which diagnoses dissociative disorders. Two additional screening measures of dissociative symptoms were used, as well as an instrument to measure IQ. RESULTS: Fifteen percent of the sample were diagnosed as having a dissociative disorder. Compared with patients without a dissociative disorder, the patients with a dissociative disorder had significantly higher median scores on the two screening measures, indicating more dissociative experiences and the presence of five distinct symptom clusters. The two groups did not differ in history of childhood abuse or IQ. CONCLUSIONS: The results support earlier findings suggesting that patients with substance abuse disorder should be routinely screened for dissociative symptoms and disorders.