The aim of the study was to analyse the prevalence of polypharmacy with antipsychotic drugs and analyse types of coprescribing episodes at the University Psychiatric Hospital in Serbia. A sample of 120 patients (198 hospitalisations) was analysed. The prevalence of polypharmacy was calculated as the proportion of patients receiving two or more antipsychotic drugs concomitantly for at least 28 days. Total daily antipsychotic drug load was calculated as the number of defined daily doses (DDDs) of drugs per patient per day. It was compared between patients receiving monotherapy and patients receiving polypharmacy. Statistics was performed using standard statistical methods. Monotherapy was prescribed during 32.3% hospitalisations (n = 64), while polypharmacy was noted in 67.7% (n = 134). Polypharmacy with two drugs was observed during 126 (63.6%) hospitalisations and three antipsychotics were prescribed concomitantly during 8 (4.1%) hospitalisations. Patients' characteristics were not significantly different between patients who received only monotherapy and patients receiving polypharmacy. Patients on monotherapy had significantly more prior hospitalisations than patients from the other group (t = 3.94, df = 119, p < 0.001). The prevalence of polypharmacy patient episodes (67.7%) is approximately 100% higher than the prevalence observed in developed European countries. The explanation of such prescribing habit of Serbian psychiatrists requires further investigation. The only distinguishing factor between patients receiving monotherapy and patients receiving polypharmacy is the number of prior hospitalisations.