OBJECTIVE To estimate the cost-utility of levodopa-carbidopa and levodopa-carbidopa-entacapone in the treatment of Parkinson disease in the Mexican Institute of Social Security in Mexico. METHODS Cost-utility analysis. Use of resources information was obtained from a retrospective cohort and was validated by a Mexican expert panel. Costs were estimated from financial information from IMSS, and are reported in US 2006 dollars. The source of utility information, measured in QALYs, and transition probabilities was a meta-analysis and a Mexican expert panel. Study perspective used public health services provider (IMSS); five years time horizon, 3% real discount rate. A decision tree with a Bayesian approach and a Markov model were used. Mean cost-utility, incremental ratios and net health benefits were estimated. The sensitivity analysis included one-way, two-way, threshold and probabilistic with Monte Carlo simulation. RESULTS Cost per utility unit for levodopa-carbidopa was \$5623 and for levodopa-carbidopa-entacapone, \$5168. Incremental cost-utility ratio using levodopa-carbidopa as a comparator was \$1585. Independently of WTP, levodopa-carbidopa-entacapone had larger net health benefits than levodopa-carbidopa. In the five years analysis, levodopa-carbidopa-entacapone showed 12.8% more utility in relation-ship to levodopa-carbidopa, with 3.5% more costs. The cost per utility unit with levodopa-carbidopa-entacapone had an accumulated decrease of 18.4% during the period of time analyzed. The acceptability curves and the component analysis of the ellipse graph showed that with the actual cost that the IMSS is investing in the treatment of Parkinson disease, the cost-utility proportion of levodopa-carbidopa-entacapone would be 80%. CONCLUSIONS Levodopa-carbidopa-entacapone had the lowest cost per unit of success in the treatment of patients with Parkinson disease compared with levodopa-carbidopa. Cost per additional utility unit of levodopa-carbidopa-entacapone was$1585. At the end of the follow-up levodopa-carbidopa-entacapone reduced annual health care costs to a greater extent than levodopa-carbidopa and provided better quality of life per patient.