Leaves and stem segments of Populus nigra were transformed with A. tumefaciens LBA4404 harboring a binary vector containing chimeric genes of NPT and 35S-omega-B.t. toxin-Nos. Nineteen regenerated kanamycin resistant plants were analyzed by DNA hybridization, out of which 10 were shown to be the candidates of transgenic plants. Insect tolerance tests showed that the transgenic plants were toxic to two lepidopteran pests, Lymantria dispar L. and Apocheimia cinerarius Erschoff. Based on the results of Southern blot of PCR products and the cluster analysis of their growth and insect resistance, three independent transgenic plants were selected, which were then propagated in the nursery field. This field test is currently in progress.