Akathisia is a frequent and distressing side effect of antipsychotic medication. Little is known about its pathophysiology. Treatment trials of serotonin antagonists in Parkinson's disease and neuroleptic-induced Parkinsonism have been disappointing, with the possible exception of akathisia which has been reported to respond favorably to ritanserin. We report first results of a single-blind trial of ritanserin in the treatment of neuroleptic-induced akathisia. Ten patients received a mean dose of 13.5 mg/day (SD +/- 5.8) ritanserin for 2 to 4 days. Treatment response was assessed by the Hillside Akathisia Scale (HAS). HAS baseline ratings were 16.4 (+/- 6). After 3 days of treatment, these values dropped to 7.4 (+/- 5.2). This amelioration was statistically significant (p = .0069 matched-pairs signed rank test). Two patients did not respond. These results, although preliminary in nature, are encouraging and warrant further studies.