To assess the need for a regional expertise in movement disorders, the numbers of patients, clinic visits, and medication changes for a new movement disorder clinic were recorded. During 3½ years, 355 patients were seen, with 1,329 clinic visits. Idiopathic Parkinson's disease was the most common diagnosis, comprising 36% of the population, followed by dystonia (17%), tremor (12%), parkinsonism (i. e., Parkinson's plus syndromes, drug-induced parkinsonism, etc.) (10%), chorea (10%), Tourette's syndrome (6.5%), and tardive dyskinesia (3.4%). Distribution of follow-up visits was similar, with Parkinson's disease (52%) being most frequent and Tourette's syndrome (3.1%) least frequent. The relative utilization of medical care by each patient group was assessed by determining the number of medication changes and the number of clinic visits per follow-up year. No differences in these measures were found using a one-way analysis of variance. Of the Parkinson's disease patients, 67% had Hoehn and Yahr stages III-IV and 77% of the clinic visits were made by this subgroup. When considered in light of the prevalence of each of the diseases, these data show a need for an expertise in movement disorders for a population base of the size we have served.