Twenty-six patients with non-Hodgkin's lymphoma have received total body irradiation (TBI) as a secondary therapy. A response was achieved with 17 patients, in six of whom it was complete. The actuarial survival rates were 50% at one year and 42% at 30 months. Best results were achieved in those with low grade histology and in those under 60 years of age. Transient marrow toxicity was the only detected significant side-effect of treatment and although it was usually severe there were no serious sequelae. TBI should be considered as a secondary therapy in non-Hodgkin's lymphoma, regardless of previous treatment.