Abstract: Micronuclei (MN) in peripheral lymphocytes from the patients with esophageal carcinoma was tested. The results was as follows:the mean frequency of MN was 5.75%o in 36patients with esophageal carcinoma, and the mean frequency of MN was 2.31‰ in 19 normal controls, and it was higher than 4‰ that was found in each of patients. The differences seen between the two groups (P0.01) were statistically significant.