OBJECTIVES: The purpose was to develop an early decision-making model for Parkinson disease (PD) and to assess the cost-effectiveness of neural transplantation (NT) compared to standard treatment in PD. METHODS: Clinical data from 79 PD patients and data from the literature regarding PD-related costs, clinical progression and life expectancy were used to develop a disease progression model according to the Hoehn and Yahr stage of PD (HY). The model was designed to model both protective and symptomatic treatment effects. Outcomes were based on a consecutive series of 14 PD patients treated with intrastriatal NT of human embryonic mesencephalic tissue, and followed for 2-10 years thereafter. Since the majority of patients receiving NT had early onset PD and were in HY3-4, the cost-effectiveness of NT was evaluated for patients belonging to these categories. Costs and quality adjusted life years (QALY) were calculated for a period of 25 years and discounted at 3 %. The calculations were made in Euro (€) (2002 prices). A sensitivity analysis was performed where scenarios regarding treatment effect, time horizon, discount rate, and the procedure cost were altered. RESULTS: Patients with a preoperative HY state of 3 and 4 improved 0.552 and 0.736 HY stages following NT, which is equivalent to 4.9 and 6.6 years in less advanced PD stages, respectively. The cost of NT, including expected costs of complications, was €36,000. The incremental cost-effectiveness ratio of NT compared to standard treatment was €11,400 for patients in HY 3 and cost saving in HY 4 patients. CONCLUSIONS: According to the assumptions made in the model, NT is cost-effective compared to standard treatment in Sweden. The main conclusions were insensitive to the assumptions made in the sensitivity analysis.