The elevated level of serum glutamic oxalacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) activity are useful in diagnosis of acute myocardial infarction and acute parenchymal disease of liver, but less useful in other disease. The author compared levels of SGOT and SGPT in 93 cases of hepatobiliary disease and 380 cases of nonhepatobiliary disease. The result are as followings. 1. The level of serum transaminase were elevated in 72(SGPT)∼84(SGOT)% of cases of hepatobiliary disease and 22(SGPT)∼31(SGOT)% of nonhepatobiliary disease. 2. The levels of transaminase were markedly elevated in 40%(SGOT) and 5%(SGPT) of hepatotiliary disease, and in only one case among 380 cased of nonhepatotiliary disease. 3. Comparison of two transaminase level revealed higher activities in SGOT than SGPT in acute viral hepatitis, liver cirrhosis and heart disease. And activities of two transaminase were parallel in chronic hepatitis, hematoma and biliary disease.