The plasmids pSUPBT and pSUPBTR were constructed with a vector pSUP2021 and the BT toxin gene in the plasmid pES 1. The plasmids constructed were introduced into the antagonistic rhizobacteria P. fluorescens KR164 by conjugation and P. fluoyescens having pSUPBT and pSUPBTR were named P. fluorescens KR164(pSUPBT) # 2, KR164(pSUPBT) # 3, KR164(pSUPBTR) # 2 and KR164(pSUPBTR) # 3, respectively. The BT toxin gene were identified in all transformants by Southern hybridization and the final product of BT toxin gene was identified only in P. fluorescens KR164(pSUPBTR) # 3 by SDS-PAGE. This crystal toxin protein were also observed in electron microscopy.