The change of lactate dehydrogenase(LDH) activity and the possibility of the existence of LDH. isozyme were examined with different parts of soybean sprout. The enzyme activity was little changed in cotyledons throughout the early stagy of germination. However, hypocotyls and roots showed the continuous decline of the enzyme activity since the radicle emerged from seeds. It was found that LDH from hypocotyls. and roots was unstable as compared with LDH from cotyledons, even at low temperature. The enzyme from hypocotyls and roots was not purified with a good yield when the purification procedure developed for LDH from cotyledons. was employed. LDH from hypocotyls and roots has the Rm value of 0.29, and 0.25 from cotyledons. The apparent Km value for LDH from cotyledons was 0.45mM with sodium pyruvate, while crude homogenate of hypocotyls or roots showed biphasic phenomenon with two Km values 0.014 and 0.45mM. The results indicate the possibility that crude homogenate of hypocotyls or roots may contain a different LDH isozyme from the LDH of soybean reported previously.