Usage of medical radioisotopes for diagnostic purposes is increasing day by day. Because of this reason, many attempts are performed for finding more efficient way for production of medical radioisotopes. One of the projectiles used for production of medical radioisotopes is neutron. In the present paper we have investigated neutron induced yield cross-sections of 51Cr, 99Mo and 133Xe radioisotopes which are commonly used in nuclear medicine as a generator for diagnostic purposes by using TALYS nuclear reaction code. For this purpose, the neutron energies for maximum yield cross-sections of 51Cr, 99Mo and 133Xe radioisotopes have been calculated and compared with the available data.