Haloperidol is widely considered a reference standard in antipsychotic therapy and is commonly used in comparative studies of the efficacy and safety of antipsychotic medication. Comparative clinical trials have shown that the novel antipsychotic agent risperidone tends to have greater efficacy (i.e., clinical response defined as a > or = 20% reduction in total scores on the Positive and Negative Syndrome Scale) than haloperidol in patients with chronic schizophrenia and poses less risk of extrapyramidal symptoms (EPS). We used DerSimonian and Laird's random-effects model to analyze pooled patient data from available randomized, double-masked, comparative trials of risperidone and haloperidol in patients with schizophrenia treated for at least 4 weeks at recommended doses. The purpose of the analysis was to determine whether there are significant overall differences in the rates of patient clinical response, prescription of anticholinergic agents, and treatment dropout. Six of the nine trials revealed in a literature search met all criteria for inclusion in the meta-analysis. The meta-analysis showed that in patients with chronic schizophrenia, risperidone therapy is associated with significantly higher response rates, significantly less prescribing of anticholinergic medication, and significantly lower treatment dropout rates than haloperidol. These results demonstrate the greater treatment efficacy associated with risperidone compared with haloperidol and suggest both a lower incidence of EPS and improved treatment compliance.