Cell nuclear DNA content was determined by flow cytometric analysis in 36 patients with esophageal carcinoma. Aneuploid DNA content was observed in 25 cases (69.4%). The relationships among DNA content, histopathologic features, and clinical characteristics were investigated. The patients with aneuploid DNA content had a high frequency of local lymph node metastasis, invasion to surrounding tissues, poor histologic differentiation, and advanced tumor stages as compared with those patients with diploid DNA content. In contrast to this, there was no correlation in patients' sex, age, and the sites of the disease.