BACKGROUND: The purpose of this study was to assess the one-year prevalence of drug use and of concurrent alcohol use among hepatitis C (HCV) patients seeking treatment from specialty HCV clinics.METHODS: Patients with confirmed HCV RNA considering HCV treatment (N = 309) were recruited from university-affiliated and Veterans Affairs medical centers.RESULTS: The prevalence of current drug use in the last year was 65% (201/309) among patients considering HCV treatment. More than one-fourth of the sample used drugs at some time in their lives but none in the last year. Only 7% (22/309) of patients reported no lifetime drug use. The prevalence of concurrent drug and alcohol use in the last year was 72% (145/201) and 52% (105/201) in the last month.CONCLUSIONS: More than half of current drug users were still consuming alcohol in the last month despite the fact that they had all been informed of the potential for accelerated liver damage from continued alcohol use. This finding suggests that achieving abstinence from drug use does not necessarily imply that abstinence from alcohol has been obtained. Integration of substance treatment and HCV treatment into a unified disease management approach might increase treatment eligibility and compliance and improve disease outcomes.