Genetic transformation is an attractive way to improve Panax ginseng C. A. Meyer by introducing new genetic materials and altering metabolic pathways that regulating the production of secondary compounds. In P. ginseng , production of transgenic plants via Agrobacterium tumefaciens is performed via somatic embryogenesis using cotyledon or embryogenic callus as explants. This chapter introduces the protocol of A. tumefaciens mediated-genetic transformation in P. ginseng .