The distribution of oligomeric proanthocyanidins in legume seeds was investigated in connection with organoleptic astringency. The seeds contained various kinds of oligomers (dimers-hexamers). The total oligomer contents were at least 0.040% in azuki beans, 0.017% in black soybeans, 0.005% in mung beans and a trace amount in regular soybeans. Each aliquot of aqueous solution of partially purified proanthocyanidin oligomers tasted astringent even at a concentration of 0.001 %(w/v). The possible contribution of oligomeric proanthocyanidins and polymeric proanthocyanidins to the astringent off-taste of legume seeds is discussed.