Two novel tannins, stenophynins A and B, isolated from the bark of Quercus stenophylla MAKINO (Fagaceae), have been characterized on the basis of chemical and spectroscopic evidence as (+)-catechin 8-C-β-D-[2", 3" : 4", 6"-bis(S)-hexahydroxydiphenoyl]-glucopyranoside (1) and (+)-catechin 8-C-β-D-[2", 3"-(S)-hexahydroxydiphenoyl-6"-galloyl]-glucopyranoside (2), respectively.