A case of co-occurrence of a mucoepidermoid carcinoma (MEC) and a squamous cell carcinoma (SCC) in the esophagus is described. The present patient was a 61-year-old man who underwent a curative esophagectomy with a regional lymph node dissection for a MEC in the lower esophagus and a SCC near the esophagogastric junction. The two lesions were endoscopically and histologically divided by a normal esophageal mucosa. The MEC of the esophagus consisted of SCC cells and signet-ring cells, and a mucin product and carcinoembryonic antigen, which were found at high levels in the blood serum before surgery, were detected histochemically in the signet-ring cells. The follow-up survey of the patients with esophageal MEC previously reported in Japan showed that most of the patients died of either local recurrence or widespread metastasis after treatment; the overall 5-year survival rate was 24.4% in the total 25 cases, and 27.7% in the 22 resected cases. However, 6 patients who died of therapeutic complications were included among these patients; furthermore, the 5-year survival rate after surgery was 29.2% in the patients treated over the last decade (1989-1998). We expect that the clinical outcome of patients treated for esophageal MEC will therefore improve in the future.