Genes for Bowman-Birk type protease inhibitors (BBIs) of wild soja (Glycine soja) and soybean (Glycine max) comprise a multigene family. The organization of the genes for wild soja BBIs (wBBIs) was elucidated by an analysis of their cDNAs and the corresponding genomic sequences, and compared with the counterparts in the soybean. The cDNAs encoding three types of wild soja BBIs (wBBI-A, -C, and -D) were cloned. Two subtypes of cDNAs for wBBI-A, designated wBBI-A1 and -A2, were further identified. Similar subtypes (sBBI-A1 and -A2) were also found in the soybean genome. cDNA sequences for wBBIs were highly homologous to those for the respective soybean homologs. Phylogenetic analysis of these cDNAs demonstrated the evolutional proximity between these two leguminae strains.Key words: cDNA cloning; Bowman-Birk inhibitors; Glycine soja; isoinhibitors; pseudogene Proteinase inhibitors are found in various plants and have been studied in the Leguminae, Gramineae, and Solanaceae.1,2) Especially, proteinase inhibitors of the Bowman-Birk family (BBIs) and the Kunitz family were discovered first in soybean seeds and have been well studied. [3][4][5] A number of functions have been proposed for BBIs, including the regulation of endogenous proteinases during germination, the storage of sulfur amino acids during dormancy, and the protection of the plant from insects and microorganisms, [6][7][8] while recent interest has focused on its medicinal utility as an antitumor agent, for instance.