The features that distinguish non-Hodgkin and Hodgkin forms of lymphoma are briefly described, together with the method employed in classifying 45 non-Hodgkin cases treated with polychemotherapy and cobalt. The results were satisfactory. Remission (complete or incomplete) was obtained in 75% and 73% of lymphocytic and histocytic forms respectively. Survival after 5 yr was 50% for cases in the 3rd stage and 11% for those in the 4th. It is felt that the 3rd stage should be regarded as a generalised form, requiring the intensive systematic management offered by combining polychemotherapy and radiotherapy.