A retrospective chart review of hospitalized patients was completed to verify whether there were differences in the prescription rate of antibiotics to patients treated with clozapine. Subjects were inpatients with a diagnosis of schizophrenia or schizoaffective disorder. Charts of all patients who received clozapine for 24 consecutive months during a period of 48 consecutive months of hospitalization were selected for the study. For each patient, we compared the number of infections treated with an antibiotic during the 24 months pre-clozapine versus the period when they were treated with clozapine. Our study suggests that the number of antibiotic prescriptions is significantly increased in patients treated with clozapine.