A 79-year-old man was admitted to our hospital because of dysphagia and weight loss. Panendoscopy revealed a tumor mass with an irregular ulcer over the lower third portion of the esophagus. Histopathologic examination revealed small round blue cells with hyperchromatic nuclei and scant cytoplasm infiltrating the submucosal region. The tumor cells were immunohistochemically positive for neuron-specific enolase, chromogranin A and synaptophysin. Electron microscopy showed tightly aggregated neoplastic cells containing dense-core endocrine granules. A clinical survey included computed tomography of the chest and a whole-body bone scan, which revealed no evidence of other tumor lesions. All data indicated that this was a case of primary neuroendocrine carcinoma of the esophagus. The patient received palliative radiation therapy and died of aspiration pneumonia three months later.