Alkali and copper contents in the precipitate formed by the reaction of Fehling's solution with hemicelluloses were determined, and the linkage between hemicellulose and copper was discussed.Glucomannan from red pine sulfite pulp and xylan from beech sulfite pulp were used as hemicellulose samples. They were dissolved in sodium hydroxide solution, and added with Fehling's solution, and copper and alkali in the precipitate formed were analyzed. The copper content in the precipitate approached to a constant value as the precipitate was washed with alkali solution. The copper content did not depend on alkali concentration and it was almost constant (0.24-0.28 mole per unit residue of hemicelluloses), although it increased a little as the concentration of Fehling's solution increased.It is supposed that the copper combines with 2, 3-glycol groups in the hemicellulose molecules.