1. To know the site of saponin synthesis in this plant, 4-years old Panax ginseng C.A. Meyer was administered with 1, 2-l4C-acetate (Na salt, 10 ucilplant) by stem injection and was continued to grow for 3 weeks and the distribution of the radioactivity in leaf, stem and root part was identified. The percentage of radioactivity recovered was about 3.99%. 2. The sliced roots or leaf discs (2g) were bathed in the reaction mixture containing sugar, ATP, NADPH, and the distribution of the radioactivity of the fractions (sugar, saponin, sapogenin) was identified. 3. It seemed that major synthesized saponins in roots and leaves are dial and triol-type, respectively. Although both types of saponins are synthesized in roots, the main saponins seemed to be dial saponins and a significant portion of triol saponins are supplied from leaves through stem.