A pilot study was undertaken to clarify the efficacy of concurrent chemoradiotherapy against locally advanced esophageal carcinoma. The 20 patients in this study had previously untreated esophageal carcinoma with evidence of T4 disease and/or distant node metastases. Chemotherapy consisted of protracted infusion of 5-fluorouracil at a dose of 400 mg/m2/day on days 1-5 and 8-12, combined with a 2-h infusion of cisplatinum at 40 mg/m2 on days 1 and 8. Radiation treatment for the mediastinum was administered 5 days per week for 3 wk at 2 Gy/day, along with chemotherapy. These schedules were repeated twice to give a total radiation dose of 60 Gy. For patients who responded, two additional courses of chemotherapy were administered. Five of the 20 patients had UICC stage III disease and 15 had stage IV. Seventeen (85%) of the 20 patients exhibited an objective response, including 6 (30%) complete responses. Local control was excellent with 10 (50%) complete responses. Toxic effects were severe. Major toxicities were leukocytopenia of grade 3 or more in 45% of the patients and esophagitis, including four perforations. There were two treatment-related deaths. The median survival time was 9 mo (range: 2 to 34+). Concurrent chemotherapy and radiotherapy was effective even for locally advanced esophageal carcinoma, but was associated with significant toxicity.