OBJECTIVES: Drug-induced parkinsonism (DIP) is an akinetic-rigid syndrome induced by pharmacologic agents that can be difficult to distinguished from idiopathic Parkinson's disease (PD). The medications potentially inducing parkinsonism include neuroleptic drugs, non-neuroleptic drugs, selective serotonin reuptake inhibitors (SSRI), and catecholamine-depleting agents (CDA). Here we examine the use of parkninsonism-inducing drugs among Medicare beneficiaries and estimate the economic burden of DIP. METHODS: We used the community-dwelling population of 1992-2000 Medicare Current Beneficiary Survey (MCBS) participants (97,999 subject-years). Bivariate comparisons were used to determine differences in the use of PD-inducing drugs between the beneficiaries with and without PD. Using multivariate model, we estimated the effect of PD-inducing drug use on the total medical expenditures. RESULTS: Among all MCBS beneficiaries, 1.63% reported having PD, 8.31% used PD-inducing drugs, and 0.93% used both anti-PD and PD-inducing drugs in a given year. Neuroleptic drugs were the most commonly used drugs inducing PD (53.82%), followed by the SSRI (41.45%), non-neuroleptic drugs (15.27%), and CDA (2.23%). More people with self-reported PD used PD-inducing drugs than people without PD (14.11% vs. 8.21%, p<0.001). Among beneficiaries using both anti-PD and DIP drugs, 65.63% used neuroleptic medications (83.21% for people not taking anti-PD medications, p<0.001), 30.00% used non-neuroleptic drugs (13.28%, p<0.001), and 35.16% used SSRI (18.59%, p<0.001). After adjusting for personal characteristics and comorbidities, the total annual medical costs were significantly higher in PD patients with psychiatric problems who were using neuroleptic drugs compared to other beneficiaries with psychiatric problems ($12109 vs. $10032, p<0.001). CONCLUSIONS: More patients with self-reported PD are taking medications known to potentially cause DIP compared to Medicare beneficiaries without PD. The neuroleptic medications are the most common PD-inducing drugs among elderly. Although more research is needed, it is likely that DIP medications are contributing to the economic and health burden of parkinsonism in Medicare beneficiaries.