99 children with non-Hodgkin's lymphoma entered the prospective, multicenter BFM study 81/83. They were treated with a four-fold stratified therapy according to clinical stage and origin of the lymphoma from B- or non-B-lymphocytes. In the BFM study 75/81, these criteria had been proven to be most relevant for prognosis. Therapy of non-B-NHL was very similar to the therapeutic concept as applied in acute lymphoblastic leukemias by the BFM group. For the NHL of B-type, a new therapeutic regimen was developed. Cytostatic drugs applied in this group were: medium dose methotrexate, cyclophosphamide in a fractionated manner of application, adriamycin, cytarabine, VM 26 and prednisone. The probability of disease-free survival was 80% after nearly 3 years for all patients. In non-B-NHL it was 89% in localized, and 79% in disseminated disease. All patients with localized B-NHL are surviving without relapse, while the probability of disease-free survival in patients with disseminated B-NHL was 67%. Thus, the therapy result in the latter group was doubled as compared to the result of the BFM study 75/81.