Background&Aims: Patients with hepatitis C virus (HCV) infection who use alcohol have been excluded from clinical trials; therefore, outcomes with antiviral therapy are unknown. The aim of the study was to determine the impact of alcohol use on HCV treatment outcomes. Methods: Subjects using alcohol were categorized as follows: no alcohol versus regular alcohol use, quantity consumed (none, < 6 drinks/day, ≥6 drinks/day), CAGE score < 2 or ≥2, and recent alcohol use (past 12 months). Patients were treated with interferon plus ribavirin. Results: A total of 4061 subjects were enrolled, and 726 (18%) received treatment. Alcohol use (past and within 12 months) reduced treatment candidacy. Past alcohol use did not affect the end of-treatment response, sustained virologic response (SVR), and treatment discontinuation rates. However, recent alcohol use resulted in higher treatment discontinuation (40%vs 26%; P = .0002) and tended to reduce the SVR (14%vs 20%; P = .06), but when patients who discontinued treatment were excluded from analysis, the trend in favor of nondrinkers for SVR disappeared (25%vs 23%). These findings were also consistent in subgroup analyses on race and genotype. Conclusions: Eligibility for anti-HCV treatment was reduced in past and recent drinkers. Recent alcohol use was associated with increased treatment discontinuation and lower SVR. However, patients who use alcohol and completed the treatment had a response comparable to that of nondrinkers. Patients with a history of alcohol use should not be excluded from HCV therapy. Instead, additional support should be provided to these patients to ensure their ability to complete treatment. Background & Aims: Patients with hepatitis C virus (HCV) infection who use alcohol have been excluded from clinical trials; therefore, outcomes with antiviral therapy are unknown. The aim of the study was to determine the impact of alcohol use on HCV treatment results. Methods: Subjects using alcohol were categorized as follows: no alcohol versus regular alcohol use, quantity consumed (none, <6 drinks / day,> 6 drinks / day), CAGE score <2 or ≥2, and recent alcohol use Patients used treated with interferon plus ribavirin. Results: A total of 4061 subjects were enrolled, and 726 (18%) received treatment. Alcohol use (past and within 12 months) reduced treatment candidacy. Past alcohol use did not affect the end of However, recent alcohol use resulted in higher treatment discontinuation (40% vs 26%; P = .0002) and tended to reduce the SVR (14% vs 20% ; P = .06), but when patients who discontinued treatment were excluded from analysis, the trend in favor of nondrinkers for SVR disappeared (25% vs 23%). These findings were also consistent in subgroup analyzes on race and genotype. Conclusions: Eligibility for anti-HCV treatment was reduced in past However, patients who use alcohol and completed the treatment had a response comparable to that of nondrinkers. Patients with a history of alcohol use should not be excluded from HCV therapy. Instead, additional support should be provided to these patients to ensure their ability to complete treatment.