The results of experiments designed to synthesize element 115 isotopes in the 243 Am + 48 Ca reaction are presented. With a beam dose of 4.3× 1018 248-MeV 48 Ca projectiles, we observed three similar decay chains consisting of five consecutive α decays, all detected in time intervals of about 20 s and terminated at a later time by a spontaneous fission with a high-energy release (total kinetic energy ̃220 MeV ). At a higher bombarding energy of 253 MeV , with an equal 48 Ca beam dose, we registered a different decay chain of four consecutive α decays detected in a time interval of about 0.5 s , also terminated by spontaneous fission. The α decay energies and half-lives for nine new α -decaying nuclei are given. The decay properties of these synthesized nuclei are consistent with consecutive α decays originating from the parent isotopes of the new element 115, 288 1 15 and 287 1 15 , produced in the 3n - and 4n -evaporation channels with cross sections of about 3 pb and 1 pb , respectively. The radioactive properties of the new odd- Z nuclei (105 115) are compared with the predictions of the macroscopic-microscopic theory. The experiments were carried out at the U400 cyclotron with the recoil separator DGFRS at FLNR, JINR.