OBJECTIVES: Prevalence of hepatitis C virus infection is approximately 2.2–3.0% worldwide (130–170 million people). A persistent infection develops in up to 85% of these patients, leading to chronic hepatitis C (CHC), a condition associated with serious liver-related complications. We aimed to perform an economic evaluation of peginterferon alpha-2a (PEG-IFN alpha-2a) plus ribavirin (RBV). METHODS: We developed a Markov model with 40 annual cycles to project cumulative cost and quality-adjusted life years (QALY) for two identical cohorts of patients aged 40 years. One cohort received PEG-IFN alpha-2a 180mcg per week plus daily doses of 1200mg of RBV during 48 weeks for genotype 1/4 or 24 weeks for genotype 2/3. The other cohort did not receive any antiviral treatment. The analysis was performed under the perspective of national public healthcare system. Only direct medical costs were accounted for; these included acquisition cost of antiviral drugs and medical attention for health states incorporated into the model. Costs (expressed in 2010 Euros) and QALY were discounted at an annual rate of 5%. Transition probabilities and utility scores were gathered from published literature and cost data was based on local sources and experts' opinion. RESULTS: Average discounted costs were estimated at €15,626 for PEG-IFN alpha-2a plus RBV and at €17,350 when no antiviral treatment is given to CHC patients, leading to overall savings of €1724 per patient. Without antiviral treatment, 9.9 QALY per patient are expected. There is a gain of 2.2 QALY for patients who are treated. Results are robust to variations in model parameters. PEG-IFN alpha-2a plus RBV was both more effective and less costly than no treatment in more than half of the simulations performed in a probabilistic sensitivity analysis. CONCLUSIONS: PEG-IFN alpha-2a plus RBV is a dominant strategy compared to given no antiviral treatment to CHC patients in Mexico.