Background Previous studies have shown that oncosis in malignant tumors might be related to cellular energy supply.The aim of this study was to detect oncosis in human esophageal squamous cell carcinoma (ESCC), and to investigate its relationship with apoptosis and microvessel density (MVD).Methods ESCC specimens were obtained from 30 patients with ESCC after surgery. Transmission electron microscopy,TUNEL, and immunohistochemistry were used to detect oncosis, apoptosis, and MVD. The relation of oncosis to apoptosis and MVD was analyzed by ANOVA, t test, and q test using SPSS 10.0.Results Transmission electron microscopy revealed both oncosis and apoptosis in the ECSS tissues. About 10% of the TUNEL-positive cells, which were considered apoptotic cells, showed the characteristics of oncosis. In the areas, where oncotic cells accumulated, apoptotic cells were rare; contrarily, where apoptotic cells gathered, oncotic cells were sparse.Compared with the tissues with a high MVD, the number of oncotic cells was increased and that of apoptotic cells was decreased in the tissues with a low MVD.Conclusions Cellular oncosis can be detected in human ESCC tissues. The distribution of oncotic cells presents a close relationship with cellular apoptosis and MVD. Oncosis might be induced by poor blood supply.