In order to compare the accuracy of two methods, conventional Reitman-Frankel method and single vial enzyme test kit method, for the determination of serum glutamic-oxalacetic tran-saminase (SGOT) activities, total 111 serum samples were examined with reference tests of revised Henry method. In the case of SGOT activity being less than 50 A.U., the two test methods and the reference method were in good agreement, respectively. However, in the range of SGOT activity over 50 A.U., which is very significant in diaguostic evaluation, the enzyme kit method excellently agreed with the reference method, whereas the value of SGOT activity determined by Reitman-Frankel method was significantly lower than by the references test. It is suggested that the method of enzyme test kit should be used for the determination of SGOT in clinical diagnosis.