OBJECTIVE: Clinical studies show that entacapone significantly increases ON time. Increases in ON time are associated with decreases in resource utilisation. This study is designed to examine the cost-effectiveness of usual care with entacapone versus usual care without entacapone in patients with Parkinson’s disease. The setting for this study was The Netherlands. METHODS: A Markov process model was constructed to model the average quality adjusted life years (QALYs) and the costs of both treatments. The 5-year model captured the impact of treatment on symptoms and disease progression. Data for the construction of the model were derived from published literature, including large multicenter randomised clinical trials in patients with end-of-dose wearing off. Costs were obtained primarily from published sources. RESULTS: The results of the baseline analysis showed a slight decrease of the 5-year total average discounted costs from NLG 111,317 to NLG 110,038, resulting in an effectiveness increase in the entacapone arm from 2.42 to 2.56 quality-adjusted life years (QALYs), a 6% increase. In addition, entacapone substantially increased "time in which patients are able to perform everyday activities" by 0.63 years. Sensitivity analyses confirmed the robustness of these findings. CONCLUSION: Entacapone is a cost-effective treatment, yielding improvement in terms of both effectiveness measures (time without severe fluctuations and QALYs), without additional cost when compared to PD treatment w/o entacapone. The additional drug costs for entacapone are offset by reductions in other costs, especially hospitalisation.