Glucose toleranee tests were performed in 26 cases of liver cirrhosis, 3 cases of hepatoma, 3 cases of aoute viral hepatitis and 15 control subjects. Tolbutamide tests were performed in 7 cases of liver cirrhosis and l hepatoma patient, who all showed severely altered diabetic glucose tolerance. The results of studies were as follows: 1) Twenty patients (77%) among 26 cases of liver cirrhosis had diabetic glucose tolerance curve.2) The results in the hepatoma and hepatitis cases were similar to that observed in patients with liver cirrhosis. 3) There was no significant relationship between the liver function tests and the glucose tolerance. 4) Diabetic glucose tolerance curve were more often observed in the patients with decompensated cirrhosis as compared to the patients with compensated cases.5) In general, delayed but almost normal response to intravenous tolbutamide loading was observed in 8 cases of liver diseases, although they all showed severely altered diabetic glucose toleranee.