In order to establish a transformation system for mulberry plants, the experiment on the transfer and expression of an exogenous gene into mulberry was carried out, using a Ti plasmid of Agrobacterium tumefaciens. The plasmid pBl121 carrying kanamycin resistant gene (Kan R) and β-glucuronidase (GUS) gene was used as an exogenous gene. Mulberry leaf discs were infected with A. tumefaciens LBA4404 carrying the plasmid, and then these leaf discs were transplanted to MS medium containing 50μg/ml kanamycin to induce the kanamycin-resistant adventitious buds. The kanamycin-resistant adventitious buds were induced from 34 percent of the leaf discs used 30 days after infection. Five of the induced adventitious buds developed into plantlets with shoots. High GUS activity was detected in these two plantlets by a spectrophotofluorometer. From these results, it was confirmed that the Kan R and GUS genes were transferred into the mulberry cells and expressed in the induced plantlets.