A phase II study of chemoradiotherapy for advanced squamous cell carcinoma of the thoracic esophagus was carried out cooperatively by nine Japanese institutions. Forty-five patients with thoracic advanced squamous cell carcinoma, who had T4 tumor or distant lymph node metastasis (M1(LYM)), were enrolled in the study for treatment with cisplatin (70 mg/m2) on days 1 and 36, and 5-fluorouracil infusion (700 mg/m2) on days 1-4 and 36-39 sandwiched around external beam irradiation (60 Gy over 6 weeks). Of the 45 evaluable patients, 37 (84.1%) completed the treatment. The overall response rate was 64.4%, and the complete response rate 8.9%. The median duration of response was 125.0 days for patients who achieved complete and partial response. The 50% median survival time was 215 days. There was one toxicity-related death due to radiation pneumonitis. The major form of toxicity exceeding grade 2 was myelosuppression and anorexia, but grade 4 toxicity was also observed (2 pulmonary, 1 severe hypoxemia, 1 severe cardiac failure and 1 mental disturbance). The results showed that this form of chemoradiotherapy had a satisfactory effect and might be useful for treatment of inoperable advanced esophageal cancer.