Objective This study evaluated the efficacy and safety of triple therapy with telaprevir (TVR), pegylated interferon α-2b (PegIFN-α-2b) and ribavirin (RBV) in Japanese patients chronically infected with hepatitis C virus (HCV) genotype 1b in real-world clinical practice. Methods A total of 106 consecutive patients with HCV genotype 1b were treated with triple therapy for 12 weeks followed by dual therapy with PegIFN-α-2b and RBV for 12 weeks. The primary end point was sustained virological response (SVR), defined as undetectable serum HCV RNA at 24 weeks after the end of treatment. Results The overall SVR rate was 87.7% (93/106 patients). Age and body weight (BW) differed significantly between patients with and patients without SVR. Multivariate analysis showed that age <67 years [odds ratio (OR) 5.03, p=0.014] and BW ≥55 kg (OR 5.87, p=0.008) were independent pretreatment factors predictive of SVR. When posttreatment factors were included, age <67 years (OR 7.30, p=0.041), rapid virological response (OR 10.60, p=0.019) and continuation of therapy (OR 14.45, p=0.012) were each independently associated with SVR. Body weight <55 kg (OR 5.96, p=0.015) and TVR initial dose ≥41 mg/kg/day (OR 5.19, p=0.017) were each independently associated with discontinuation of therapy. Discontinuation rates decreased in inverse proportion to the percentage of patients with an initial TVR dose of 1,500 mg/day. Conclusion For TVR-based triple therapy, continuation of therapy is the most important predictor of SVR. Patients who are likely intolerant of standard-dose TVR should receive reduced initial doses of TVR to avoid discontinuation of therapy.