Summary. Glucose, fructose, galaotose, sucrose, mfaltose, melibiose, raffinose, and stachyose were identified in the leaves, bark, 'roots, and berries of Vitis vinifera L. var. Thompson Seedless. In addition to these sugars, verbascose and manninotriose were found in the leaves and bark. Malic, tartaric, citric, isocitric, ascorbic, cis-aconitic, oxalic, glycolic, glyoxylic, suc- (17) showed that 12 to 27 % of the total acidity and 0.5 to 12 % of the reducing sugars in grape leaves is not accounted for by malic and tartaric acids and glucose and fructose, respectively. The introduction of chromatography has greatly facilitated the study of sugars and organic acids by offering a relatively simple method of separating and identifying individual componenlts of rather complex mixtures of these substances. For a review o,f the literature pertaining to organic acids and sugars in grapevi,nes, see Amerine (1, 2), Amerine and Winkler (3), and Kliewer (13,14,15).In the present study, 11 different parts of the grapevine were investigated for their free organic acid and sugar components. Various tests were conducted to identify individual organic acids and sugars. Glucose, fructose, sucrose, malate, tartrate, and citrate were determined quantitatively in the various parts