Purpose Traditionally, radiation treatment dosimetric plans are evaluated by degree of PTV coverage by prescribed dose and the fulfillment of QUANTEC limitations on OARs. In the case of hypofractionated SBRT irradiation plans should be optimized with respect to optimal fractionation and total delivered dose. In this case one could use macroscopic radiobiological criteria, namely TCP and NTCP. The aim of the work is to optimize prostate cancer SBRT treatment basing on TCP/NTCP criteria in the range of total doses from 33.5 Gy to 38 Gy delivered in 4 or 5 fractions. Methods SBRT treatment plans based on VMAT dose delivery technique (4 full arcs) were made in Elekta MONACO planning system v. 5.10. Five patients with T1 and T2 prostate cancer were planned to total doses from 33.5 Gy to 38 Gy in four or five fractions. Differential DVHs were used for simulation of TCP values using Niemierko model and Stavrev-Niemerko model assuming that for prostate cancer α β = 1.5 ± 0.5 Gy. For calculation of NTCP the models of Niemierko and Kallman were used. All plans were compared basing on UTCP = TCP 1 - NTCP . NTCP values were calculated for the forward wall of rectum as the most irradiated OAR. Thus, using all TCP and NTCP models four variants are possible for each total dose of irradiation and fractionation. Results All plans were planned to the best of the medical physicist experience resulting in 98% of PTV covered by 98% of prescribed dose, and 100% of CTV covered by 99% of dose. CI and HI were equal to 0.99. For all five patients the best plans resulted in UTCP values 0.97–0.98 that were obtained for two variants of irradiation: 33.5 Gy in 4 fractions or 36 Gy in 5 fractions. Further increase of dose for both fractionations resulted in significant damage of the OAR. For all plans TCP values were larger than 0.97 tending to unit with increase of total dose as expected. Conclusion Simulation of TCP/NTCP values of the different VMAT irradiation plans was carried out using different models. The results allowed to find the optimal plan with respect to fractionation and dose per fraction.