One hundred and eleven patients with advanced-stage, high-grade histology non-Hodgkin's lymphoma were studied over a 7-yr period and were treated with one form of chemotherapy and radiotherapy. Multivariate analyses were carried out to identify factors which could predict a favourable prognosis. A complete response, low serum LDH and absence of clinical evidence of liver involvement were associated with long-term survival. The presence of 'B' symptoms, bone marrow involvement, low serum albumin and male sex predicted a reduced chance of achieving a complete remission. For those patients who achieved a complete response, the subdivision of histologies, particularly according to the Kiel classification, was the only significant factor predictive of prolonged relapse-free and overall survival. This confirms the importance of identifying different histological subgroups of lymphoma when considering treatment planning.