Using a records-linkage system, we determined the frequency and distribution of brain autopsies in residents of Olmsted County, Minnesota, in whom parkinsonism developed during 1976 through 1990. Of the 364 incident cases identified, 235 patients were deceased at the time of record abstraction. The overall autopsy rate was low (23%). Diagnostic certainty (for PD), diagnostic type (PD versus other parkinsonism), sex, age at death, and location at death were important selection factors for autopsy.