The recently promulgated Health Care Finance Administration guidelines regarding the use of neuroleptic medications for nursing home residents do not offer criteria for the frequency or nature of the required assessments of neuroleptic-induced parkinsonism (NIP). NIP has been poorly characterized in the elderly and empirical evidence on which to base guidelines for monitoring NIP is sparse. We examined the onset of NIP in 12 closely monitored, elderly psychiatric inpatients diagnosed with dementia being treated with perphenazine. Significant increases in the Simpson Extrapyramidal Side Effect Scale total score were detected by day 4 of treatment with perphenazine at a mean dose of 8.0 mg. This increase was highly correlated with the final NIP severity. This is the first report to demonstrate that routine screening of elderly patients can detect NIP within days of the initiation of neuroleptic treatment. Early detection of NIP may allow for effective intervention to reduce the ultimate severity and associated morbidity of NIP.