Summary. Patients with genotype I chronic hepatitis C virus (HCV) infection with late virological response to therapy have low sustained viral response (SVR) with standard 48 weeks of therapy and may benefit from extended therapy. We performed a systematic review and meta-analysis of five studies to compare the outcome of 48 weeks vs 72 weeks treatment in treatment naïve chronic hepatitis C genotype I patients with late virological response. The end of treatment response with extended 72 weeks of treatment compared to standard 48 weeks of treatment was similar 48% and 56%, respectively, with pooled odds ratio (OR) (0.85; 95% CI 0.52–1.37). However, the SVR rates were higher with 72 weeks of treatment compared to 48 weeks treatment 32%vs 25% with pooled OR of 1.67 in favour of extended duration therapy (95% CI 1.16–2.40). This was because of lower relapse rates with extended duration therapy (35%vs 55%) with OR of 0.39 in favour of 72 weeks therapy (95% CI 0.25–0.61). There was no heterogeneity. No publication bias was noted as assessed by Egger’s test. Extending the treatment duration from 48 to 72 weeks in genotype 1 infected patients with late virological response improves SVR. Thus, therapy extension in genotype 1 late viral responders (LVR) may be a consideration to improve treatment response; however, the proportion of patients with LVR that might benefit from 72-week therapy appears to be small.