[en] In continuation of our work on investigation of the neutron-deficient plutonium isotopes we carried out the experiments aimed to produce new isotopes ^228,229Pu. The isotope ²²⁸Pu has been produced in the bombardment of the ²⁰⁸Pb target with a beam of ²⁴Mg and the isotope ²²⁹Pu - in the reactions of ^207,208Pb targets with ²⁶Mg projectiles. The isotopes were identified after in-flight separation from the beam and target-like particles by the VASSILISSA electrostatic separator and implantation into silicon strip detectors. The assignment of unknown α-decays was made by establishing their genetic position and time correlations with those belonging to known α-decay chains. The α-decay energies of ^228,229Pu were measured to be (7810 ± 20) keV and (7460 ± 30) keV, respectively. (orig.)