Abstract: This article reports the change in the serumal LDH&LDH isoenzymes in 28 patients with esophageal cancer and、6 Fatients with cancer of the gastric cardia, Signif icant elevation of total LDH activity was seen in 75% of the 28 patients with esophageal cancer and in all of the 6 patients with carcinoma of the gastric cardia. Characteristic of the change in LDH isoenzyme pattern was the signif icant.elevation of LDH 4 and LDH-5, with 85.71% of the LDH-4 elevation，&78.57% of LDH-5 rise seen in the 28 cases of esophageal cancer. As for the 6 cases of cancer of the gastric cardiac all had elevation of LDH一4 and LDH-5, The degree of elevation was, correlated to that of oncogenesis.