The endosperm cells and the umbiliform layer of ginseng (Panax ginseng C.A. Meyer) seed are studied with light and electron microscope. Differentiated mitochondria, ER cisternae, proplastids and ribosomes are characteristically observed in the endosperm cells of matured seed. The cell inclusions contain the protein bodies and the spherosomes. Protein body contains, in proteinaceous matrix, globoids and crystalloids. Particularly the crystalloids have the lattice structure, and the formation of globoids is closely related with ER. Umbiliform layer has the positive reaction on alcian blue (pH 2.5) and the metachromasis on the toluidine blue. The umbiliform layer is formed by autolysis of endosperm cells, and composed of the deformated cell wall and the lipoprotein bodies. Particularly a part of the lipoprotein body and the fibrilar network structure have the positive reaction on acid phosphatase.