OBJECTIVE Recently, atypical antipsychotic agents have primarily been used in pharmacological treatment of schizophrenia because of the fewer associated adverse effects. Blonanserin is a novel atypical antipsychotic recently introduced to treat patients with schizophrenia in Japan and South Korea. In this study, we examined the efficacy of switching antipsychotic medications to blonanserin monotherapy in patients with chronic schizophrenia with associated hyperprolactinemia. METHODS Ten schizophrenic patients (5 males and 5 females) with hyperprolactinemia were recruited. Clinical data before (baseline) and 12 weeks after (end point) switching to blonanserin monotherapy were assessed using the Brief Psychiatric Rating Scale score, Drug-Induced Extrapyramidal Symptoms Scale, and serum prolactin levels. RESULTS The mean (SD) blonanserin dosage was 14.8 (3.8) mg/d. After switching to blonanserin, there were significant improvements in the Brief Psychiatric Rating Scale in the patients from both sexes. Moreover, serum prolactin levels in the female patients significantly decreased to within reference range. There were no additional adverse effects observed with the blonanserin treatment. CONCLUSIONS Switching to blonanserin can reverse medication-induced prolactin elevations found in female patients- and blonanserin is a suitable antipsychotic for schizophrenic patients.