Sertindole is a novel antipsychotic agent with high selectivity for the mesolimbic dopaminergic pathway and nanomolar affinities for dopamine D2, serotonin 5-HT2, and norepinephrine NE alpha 1 receptors. This 40-day randomized, placebo-controlled, dose-ranging multicenter study was designed to assess the effect of sertindole on previously neuroleptic-responsive, hospitalized schizophrenic patients (n = 205). Sertindole doses began at 4 mg/day and were increased to 8, 12, or 20 mg/day, depending on randomization. Efficacy measures included the Positive and Negative Syndrome Scale (PANSS), Brief Psychiatric Rating Scale (BPRS), and Clinical Global Impression (CGI). Extrapyramidal symptoms (EPS) were assessed by movement rating scales, EPS-related adverse events, and use of anti-EPS medications. A dose-related improvement was observed for PANSS, BPRS, and CGI, with statistically significant mean differences (P < 0.05) between placebo and 20-mg/day sertindole (decreases from baseline of -5.8 versus -16.9 for PANSS, -4.8 versus -10.4 for BPRS, respectively). The differences in CGI final improvement score between placebo and 20-mg/day sertindole were 3.8 versus 2.9, respectively. EPS-related events were comparable in the placebo and sertindole groups. In conclusion, sertindole 20 mg/day was effective, well tolerated, and not associated with significant motor system abnormalities.