In order to investigate the influence of gamma-irradiation on fatty acids in ginseng, ginseng were irradiated with various radiation doses(0-50 Mrads). The results are as follows. 1. With increasing dose, standard fatty acids were decreased in the order of linolenic acid, linoleic acid and oleic acid, and their contents in the presence of oxygen were decreased more t than that in the absence of oxygen. 2. Changes of lipid content in white ginseng by gamma irradiation were varied with the samples, but the changes of crude lipid and purified lipid in a sample were showed same fashion. 3. The fatty acid contents in white ginseng were decreased by gamma irradiation in the order of linolenic acid, linoleic acid, oleic acid, stearic acid and palmitic acid.