In a randomized, prospective trial from 1974-1978, 73 patients with non-Hodgkin's lymphomas in clinical Stage I or II were treated with extended field radiotherapy alone (RT) or RT plus adjuvant chemotherapy with vincristine, streptonigrin, cyclophosphamide and prednisone (RT + CT). With a median follow-up time of five years, 54% have relapsed in the RT group versus only 10% in the RT + CT group (P less than 0.01). There is no statistical difference in the overall survival yet, but 13/14 deaths in the RT group versus only 3/12 in the RT + CT group were due to progressive disease. Among patients with unfavorable histology, 13/22 in the RT group have died from disease progression against 3/34 in the RT + CT group (P less than 0.01). The results are in agreement with those from two other series published in detail. Based on these results we therefore recommend to use adjuvant CT with RT in all Stage I-II patients with unfavorable histology. Further observation is necessary before a conclusion can be drawn for the lymphoma patients with more favorable histology.