The transfer of genetic material into soybean tissue was accomplished by using an avirulent strain of Agrobacterium tumefaciens which contained the binary vector pGA482. The method used for transformation requires no tissue culture steps as it involves the inoculation of the plumule, cotyledonary node, and adjacent cotyledon tissues of germinating seeds. The identification of neomycin phosphotransferase (NPT) II enzyme activity in the tissues of 16 (R(0)) soybean plants indicated that the plant expressible Nos-NPT II gene, contained within the T-DNA region from pGA482, had been transferred at least into somatic tissues. Putative transformed R(0) soybean plants were advanced to produce R(1) plants which were also assayed for the presence of the transferred Nos-NPT II gene. The combined results of these assays indicated that about 0.7% of the surviving inoculated seeds yielded transformed tissues in the R(0) plant, and that about 1/10 of these plants yielded transformed R(1) plants. The presence of the Nos-NPT II gene in DNAs isolated from both R(0) and R(1) plant was demonstrated by using genomic blot hybridization and polymerase chain reaction methods. Integration of this gene into the soybean genome was demonstrated for three R(1) soybean plants.