Parkinson's disease (PD) causes significant expense for the national health care system due to its chronic progressive course, the duration of the disease, the high prevalence and the devastating prognosis. In Germany more than DM 320 million are spent for drugs to alleviate parkinsonian symptoms. The aim of this study was to calculate the economic burden of PD by assessing direct medical costs. Forty patients suffering from idiopathic PD were interviewed at an office of neurological specialists and at an outpatient movement disorder clinic about their use of health care resources 3 months prior to the study. The total annual costs reported were DM 14,500, consisting of DM 6500 for drug therapy and DM 8000 for other medical services, including hospital inpatient care (DM 5600), outpatient care (DM 700), medical sundries (DM 1100) and physiotherapy (DM 600). The costs were positively correlated to the extent of the disease (Hoehn and Yahr stage; HY) and the occurrence of motor fluctuations/dyskinesias. We found that both drug-therapy expenses and total medical costs doubled from HYI to HYIV. The rarely employed s.c. therapy with apomorphine additionally increased the costs of drug therapy in HYV. The occurrence of fluctuations/ dyskinesias also increased medical expenses by approximately a factor of two. Indirect burden due to increased days off of work, unemployment and earlier retirement are also significant in Parkinson's disease. This study includes that a treatment which could prevent or retard disease progression as well as a treatment that delays or reduces motor complications would not only ameliorate the situation of patients suffering from PD, but would also lead to significant reductions in cost for the national health care system.