Objectives: The goal of this study was to explore antipsychotic medication prescribing practices in a sample of 86,034 patients discharged from state psychiatric inpatient hospitals and to find the prevalence of patients discharged with no antipsychotic medications, on antipsychotic monotherapy, and on antipsychotic polypharmacy. For patients discharged on antipsychotic polypharmacy, the study explored the adjusted rates of antipsychotic polypharmacy, the reasons patients were discharged on antipsychotic polypharmacy, the proportion of antipsychotic polypharmacy by mental health disorder, and the characteristics associated with being discharged on antipsychotic polypharmacy., Methods: This cross-sectional study analyzed all discharges for adult patients (18 to 64 y of age) from state psychiatric inpatient hospitals between January 1 and December 31, 2011. The relationship among variables was explored using χ, t test, and analysis of variance. Logistic regression was used to determine predictors of antipsychotic polypharmacy., Results: The prevalence of antipsychotic polypharmacy was 12%. Of the discharged patients receiving at least 1 antipsychotic medication (adjusted rate), 18% were on antipsychotic polypharmacy. The strongest predictors of antipsychotic polypharmacy being prescribed were having a diagnosis of schizophrenia and a length of stay of 90 days or more. Patients were prescribed antipsychotic polypharmacy primarily to reduce their symptoms., Conclusions: Antipsychotic polypharmacy continues at a high enough rate to affect nearly 10,000 patients with a diagnosis of schizophrenia each year in state psychiatric inpatient hospitals. Further analysis of the clinical presentation of these patients may highlight particular aspects of the illness and its previous treatment that are contributing to practices outside the best-practice guideline. An increased understanding of trend data, patient characteristics, and national benchmarks provides an opportunity for decision-making that is sensitive to the patient's needs and cognizant of the hospital's accomplishments in adopting best practices.