The carcinosarcoma of the esophagus is a rare malignant neoplasm consisting of both carcinomatous and sarcomatous components. A case of so-called carcinosarcoma of the esophagus is described herein. A 69-year-old man presented with dysphagia and was admitted to our hospital. Imaging studies revealed a localized ulcerative tumor in the middle intrathoracic esophagus without any invasion or metastasis. The patient was initially thought to have squamous cell carcinoma and underwent subtotal esophagectomy with lymphadenectomy. Final diagnosis of the tumor was so-called carcinosarcoma of the esophagus. The patient had an uneventful postoperative course and showed no evidence of recurrence or metastasis in the 4-year postoperative period.