Abstract: Ten cases of undifferentiated carcinoma of esophagus were studied by histopathology. Of these. 2 cases were the metastic lymph node and 8 cases were resected esophagus. 7 of 10 cases were developed in middle third of the esophagus and 3cases in lower third. On the basis of tbe size, morphology, and structure of thecells in the undifferentialed carcinoma, they were classified as small cell, largecell, and the mixted type of small and large cell. The histogenesis of esophagealundifferentialed carcinoma was also discussed in the article. Followed informationsuggested 66% of total cases died of thier disease in one year (6/9). The prog-nosis of large cell type was better than the two other types.