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. Current standard of treatment includes Peginterferon (PEG-IFN) alpha plus ribavirin (RBV). We aimed to compare two different options of PEG-IFN alpha. 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 moderate CHC patients without cirrhosis aged 40 years. One cohort received PEG-IFN alpha-2a 180mcg per week and the other received PEG-IFN alpha-2b 1.5 mcg/Kg weekly, both combined with daily doses of 1,200mg of RBV during 48 weeks for genotype 1/4 or 24 weeks for genotype 2/3. The analysis was performed under the perspective of national public health care 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 €16,854 for PEG-IFN alpha-2a plus RBV and at €18,247 for PEG-IFN alpha-2b plus RBV, leading to overall savings of €1,393 per patient when PEG-IFN alpha-2a is used. Discounted QALY were 12.29 for PEG-IFN alpha-2a and 12.17 for PEG-IFN alpha-2b. Results are robust to variations in model parameters. CONCLUSIONS: PEG-IFN alpha-2a plus RBV is a dominant strategy compared to given PEG-IFN alpha-2b treatment to CHC patients in Mexico.