During the period of 1963. 1. -1973. 12. a total of 100 cases of malignant lymphoma has been treated with suoervoltage X-ray and electron therapy with 15 MeV Betatron. Of these cases, reticulum cell sarcoma was observed in the 83 cases, and Hodin's disease in the 10 cases in the histological findings. The staging of malignant lymphoma has been estabilished by Ann Arbor Congress (1971). Reticulum cell sarcomas were classified into St-Ⅰ 9 cases, St-Ⅱ 34 cases, St-Ⅲ 32cases and St-ⅳ 8 cases. After the first treatment, recurrence and metastasis ocurred in 28 cases (28%). The doses of excellent effective were more than 4000 reds/4 2 weeks. Crude 5 year survival rate of reticulum cell sarcoma was 50% in St-Ⅰ, 42% in St-Ⅱ, and 0% in St-Ⅲ and ⅳ, respectively.