Studies on the chemical constituents from a Korean wild mushroom, Phellinus ribis, were carried out. A triterpenoid, two peroxysterols, and a chlorobenzene compound were isolated from the hexane soluble fraction of the methanol extract of dried fruiting bodies of the basidomycetes. Those compounds identifed were 3-hydroxy-20(29)-lupen-28-oic acid (betulinic acid), 5, 8-epidioxy ergosta-6, 22-dien-3-ol(ergosterol peroxide), 5, 8-epidioxyergosta-6, 9( 11), 22-trien-3-ol (dehydroperoxyergosterol), and 1, 2, 4, 5-tetrachloro-3, 6-dimethoxybenzene. Structural studies were carried out on molecular species of a ceramide and cerebroside isolated from the chloroform soluble fraction of the methanol extract. For ceramide, the major component fatty acids were a-hydroxy fatty acid isomers of C_(22:00) ~ C_(25:00); the predominant long-chain bases were trihydroxy sphinganine of C_(17) ~ C_(18). The structure of a cerebroside containing mono-sugar was assumed that the long-chain base was C_(l9:2) sphingadienine; the major fatty acids were C_(16)~C_(15) α-hydroxy fatty acid isomers.