A 72-year-old male with a chief complaint of dysphagia was admitted to our hospital. Upper gastrointestinal endoscopic examination showed double cancers with thoracic esophageal cancer in the middle esophagus and gastric cancer in the antrum. Pathological examinations of the double cancer revealed the first one to be moderately-differentiated squamous cell carcinoma and the second to be well-differentiated adenocarcinoma. Computed tomography (CT) of the chest and abdomen showed no distant or lymph node metastases. Clinical stagings of the double cancer were stage II (T2N0M0)in esophageal cancer and stage I A (T1N0M0) in gastric cancer. The patient received neoadjuvant chemotherapy using docetaxel, CDDP and 5-FU. After 2 courses of chemotherapy, the adverse event was grade 2 in leucopenia and grade 2 in alopecia. Repeated macroscopic and histological examinations after chemotherapy revealed that the esophageal cancer had significant reductions in the size of tumors, leading to a partial response, and the gastric cancer had disappeared, leading to a complete response. He underwent thoracoscopy-assisted esophagectomy in the prone position, and laparoscopy-assisted gastric tube reconstruction. This neoadjuvant chemotherapy of docetaxel, CDDP and 5-FU might be effective and tolerable as with patients with double cancer of esophageal and gastric cancers.