Objective: Antipsychotic polypharmacy in the elderly usually results in higher rates of interactions, side effects and increased cost. This research was designed to observe the benefits of replacing polypharmacy with a single medication in elderly patients with chronic schizophrenia. Methods: This was a quasi-experimental, prospective, descriptive and analytical clinical trial. A survey was performed at the long stay public and academic Tehran Razi Mental Hospital. From the initial 157 conveniently access patients, 59 cases were selected based on inclusion and exclusion criteria. Before intervention, 7 patients did not participate in the study due to the recent diagnosis of new medical conditions. Fifty-two (52) cases (males=13 and females= 39) entered and completed the 36 week research time period. At baseline 40 patients were receiving two types of antipsychotics, whereas, 11 patients were receiving three types and only 1 patient was receiving four types of antipsychotic drugs. In the pre-intervention period, the approval of the University`s ethics committee and the informed consents of the patients' relatives were obtained. Systematically, the patients` multiple antipsychotics were switched to a single medication, risperidone. After determining the equivalent dose of risperidone, it was started at 1 mg/day for all patients. After a 3-6 week cross-titration period, the patients reached the previously determined equivalent risperidone doses and completed 36 weeks until the end of the study. Clinical assessments including the Brief Psychotic Rating Scale (BPRS), Global Assessment of Functioning (GAF), and Extra-Pyramidal Syndrome (EPS) Scale were applied on a weekly basis for a 36 week period. Results: The mean BPRS scores of the participants showed statistically significant improvement after the 9 th week of intervention. Improvements were observed in all symptom dimensions of the BPRS (positive, negative and general schizophrenic symptoms). At the end of 36 weeks of risperidone use, 90.1% of the patients achieved at least a 50% reduction in their symptoms. Additionally, functional improvement and a lower incidence of extrapyramidal side effects were also achieved after 36 weeks of risperidone use in the study population. Conclusion: Risperidone may be considered safe as a monotherapy alternative for elderly patients with chronic schizophrenia who are being treated with multiple concomitant antipsychotics. This replacement may result in some clinical benefits and fewer side effects.