Twenty-three patients with squamous cell carcinoma of the esophagus were treated with low-dose carboplatin and radiation therapy. Patients received 1.6 Gy-fractions daily; the total dose was 50-70 Gy for 14 unresectable cases, and 30-40 Gy for 8 resectable cases as preoperative irradiation. Carboplatin (30 mg/m2/day) was administered intravenously just before the irradiation; total dose was 1,100-2,000 mg for the unresectable cases, and 750-1,200 mg for the resectable cases. The response rate of the unresectable tumors was 86% (CR 5, PR 7, and NC 2). Three of the five CR patients were alive without recurrence for more than 2 years. The response rate of the resectable tumors was 75%. Although major toxicity was bone marrow suppression, there were no serious complications. These results suggest that this regimen is effective for patients with squamous cell carcinoma of the esophagus.