Hospital costs for chronic schizophrenic patients consume a major share of the cost of mental health care. Despite the success of numerous community mental health programs, repeated hospital admission of schizophrenic patients is a significant problem. Effective therapy and compliance with that therapy are two important factors in reducing hospitalization. Adverse effects of antipsychotic agents, particularly extrapyramidal symptoms (EPS), negatively influence compliance. A new antipsychotic agent, risperidone, has demonstrated efficacy against both positive and negative symptoms of schizophrenia and has been associated with a low incidence of EPS. To assess the potential of risperidone therapy to reduce the number of days in the hospital, a retrospective analysis was undertaken of data from a year-long clinical trial of risperidone. For 27 patients who had completed 365 days of open-label therapy with risperidone, the number of hospital days during this period was compared with the number of hospital days in the preceding 365-day period, when the patients were receiving conventional antipsychotic medication. The mean number of hospital days was reduced from 106 to 85 days, for a 20% reduction (P = 0.003) after the initiation of risperidone. Three subgroups of patients were apparent: (1) those who had spent no time in the hospital in the pre-risperidone year, (2) those who had been continuously hospitalized in the pre-risperidone year, and (3) those who had spent part of the pre-risperidone year (3 to 165 days) in the hospital. A 73% reduction (P = 0.0009) in mean hospital days (from 49 to 13 days) was achieved in the third subgroup (n = 14). These findings suggest that risperidone may have a role in reducing hospital days for the chronic schizophrenic population.