Praziquantel (PZQ) is a drug which is used by choice to schistosomiasis treatment. Currently, it is used in malaria treatment. PZQ undergoes extensive metabolism in human body, mainly in liver, by two cytochrome P-450 isoenzymes 2B1 and 3A. As a result of these biotransformations, numerous mono- and dihydroxylated derivates in B, C and D rings are formed. Only one metabolite has been identified and described, it is 4-hydroxypraziquantel (4-OH-PZQ). So for, the metabolites out of PZQ biotransformation were obtained under the influence of Cunnighamelle echinulata and Beauveria bassiana. There were the derivatives in position C7 and in D-ring (position is unknown). In our research, we would like to create a new model of PZQ biotransformation in vitro. For such purpose, Saccharomyces cerevisiae were used. The results of PZQ biotransformation in vitro under the influence of Saccharomyces cerevisiae were compared with computer simulation of PZQ metabolism performed by the use of Metabol Expert program.