BACKGROUND Data are limited on the efficacy and safety of pegylated interferon plus ribavirin for patients with hepatitis C virus genotype 1 (HCV-1) receiving hemodialysis. OBJECTIVE To compare the efficacy and safety of combination therapy with pegylated interferon plus low-dose ribavirin and pegylated interferon monotherapy for treatment-naive patients with HCV-1 receiving hemodialysis. DESIGN Open-label, randomized, controlled trial. (ClinicalTrials.gov: NCT00491244). SETTING 8 centers in Taiwan. PATIENTS 205 treatment-naive patients with HCV-1 receiving hemodialysis. INTERVENTION 48 weeks of pegylated interferon-α2a, 135 µg weekly, plus ribavirin, 200 mg daily (n = 103), or pegylated interferon-α2a, 135 µg weekly (n = 102). MEASUREMENTS Sustained virologic response rate and adverse event-related withdrawal rate. RESULTS Compared with monotherapy, combination therapy had a greater sustained virologic response rate (64% vs. 33%; relative risk, 1.92 [95% CI, 1.41 to 2.62]; P < 0.001). More patients receiving combination therapy had hemoglobin levels less than 8.5 g/dL than those receiving monotherapy (72% vs. 6%; risk difference, 66% [CI, 56% to 76%]; P < 0.001). Patients receiving combination therapy required a higher dosage (mean, 13 946 IU per week [SD, 6449] vs. 5833 IU per week [SD, 1169]; P = 0.006) and longer duration (mean, 29 weeks [SD, 9] vs. 18 weeks [SD, 7]; P = 0.004) of epoetin-β than patients receiving monotherapy. The adverse event-related withdrawal rates were 7% in the combination therapy group and 4% in the monotherapy group (risk difference, 3% [CI, -3% to 9%]). LIMITATION Open-label trial; results may not be generalizable to patients on peritoneal dialysis. CONCLUSION In treatment-naive patients with HCV-1 receiving hemodialysis, combination therapy with pegylated interferon plus low-dose ribavirin achieved a greater sustained virologic response rate than pegylated interferon monotherapy. PRIMARY FUNDING SOURCE National Center of Excellence for Clinical Trial and Research.