Abstract: Anticomplementary competence (ACC) was measured by an assay of inhibitory complement hemolysis in 51 patients with esophageal diseases and 37 normal subjects.There was no significant difference in sera ACC between health controls and patients with benign esophageal disease (BED). The ACC of cancer patients were significantly higher than that of the healthy and BED groups. The ACC of the patoents with different stage of esophageal cancer patients was higher than that of the healthy subjects. It suggests that the higher ACC might be one of causes of immune inhibitions induced by the tumor cells.