OBJECTIVE: To determine cost-utility of the treatment alternatives of C virus hepatitis (CVH) in the Mexican Institute of Social Security (IMSS): a) Peginterferon, b) Peginterferon plus Ribavirin, c) Peginterferon plus Ribavirin plus Thymosin in those patients that did not respond to interferon plus Ribavirin, and d) and finally, not using any drug. METHODS: A cost-utility analysis was performed using a decision tree and a Markov model to simulate a cohort of 30-year-old male patients with CVH without chronic complications. The follow-up was till their death. The cost information was gotten from a Mexican expert panel and effectiveness data were taken from a clinical trial in Mexican population. The perspective used was institutional and a 3% discount rate was applied for costs and effectiveness. Costs were reported in 2005 US dollars. The sensitivity analysis performed included one-way, two-way, threshold and probabilistic. Acceptability curves and health net benefits were estimated. RESULTS: The most costly and least effective option was not using any drug, with $4716 per QALY. The alternative with less cost per QALY was the one that included Thymosin ($2246) followed by Peginterferon plus Ribavirin ($2492) and Peginterferon alone ($3229). CONCLUSIONS: The alternatives of not using any drug and the one based on Peginterferon were dominated. Triple therapy (Peginterferon plus Ribavirin plus Thymosin) was the most expensive and effective. Therefore the decision about using triple therapy and Peginterferon plus Ribavirin will depend on willingness to pay.