TMP-SMX is the first choice drug to prevent Pneumocystis jiroveci pneumonia (PCP) in hemato-oncology patients. The utilization of alternative drugs (Pentamidine – Dapsone) was suggested in some protocols in hemato-oncology. It seems that there is an increase in the utilization of alternative drugs. The aim of the study was to evaluate the utilization of different drugs to prevent PCP and to identify the reasons which lead to the utilization of alternative drugs.