Progressive dysphagia in a 53 year old man was caused by a giant polypoid tumor in the lower intrathoracic esophagus. Radical transthoracic esophagectomy and esophagogastrostomy were carried out. Microscopic examination of the tumor revealed a true carcinosarcoma, composed of a mixture of basaloid squamous cell carcinoma and chondrosarcoma with multiple cartilagenous productions. Carcinoma metastases were found in the subcarinal and perigastric lymph nodes. Immunohistochemically, squamous area displayed strong positive to cytokeratin, and basaloid area showed positive immunoreaction to high molecular weight cytokeratin (34${eta}$E12). Spindle cell sarcoma reacted to vimentin and smooth muscle actin. Chondrosarcomatous area reacted to vimentin and S-100 protein. He received postoperative chemotherpy and radiotherapy. He has been free of disease for 11 months.