The results of biochemical studies conducted in 42 patients with Huntington's chorea are presented. The authors marked the decrease of tolerance to glucose, the increase of cholesterol concentration in the blood serum in some patients. Uric acid concentration in the blood serum and its excretion with urine were decreased in all examined patients. Ceruloplasmic activity in the patients' blood did not differ from the normal level. Cuprum concentration in the blood serum and the patients' urine was within the normal fluctuations.