Twenty-five patients with esophageal cancer less than 5 cm in length receiving radical radiotherapy alone were studied to consider the radicality of this therapy for early esophageal cancer. The relative five-year survival rate for the 25 patients was 41%, which was better than 23% for 60 patients receiving radical radiotherapy and many reported results. And for 11 stage I patients, a five-year survival rate of 79% could be obtained. Summing up Japanese results reporting survival rates by tumor length revealed that crude five-year survival rates were 21.5% for tumors less than 5 cm and 4% for tumors more than 5 cm long, respectively. Radiotherapy can be considered to be among the effective modalities for the treatment of early esophageal cancer.