Treatment advances in Hodgkin's disease have resulted in many patients achieving long-term survival, and the late complication of second malignancies is being increasingly recognized. The occurrence of Burkitt's lymphoma following chemotherapy or combined-modality treatment for Hodgkin's disease has previously been documented. Its development has not, to the best of our knowledge, been described following irradiation alone. We report a male patient with Hodgkin's disease treated by mantle irradiation who subsequently died from Burkitt's lymphoma. Theories of pathogenesis are presented. (Topical Term)