Total body irradiation (TBI) offers a new dimension in the treatment of chronic lymphocytic leukemia (CLL), a disease heretofore refractory to effective management. Excellent responses were observed in 50 57 (88%) consecutive patients with active CLL treated since 1964, and complete remissions were achieved in 22 57 (39%). Toxicity was acceptable and was minimized by combining TBI and chemotherapy in attenuated doses of each modality. The responders had a modified natural history of disease as evidenced by prolonged survival, improved quality of life, and even restoration of immunologic competence in some cases. Benefit was particularly evident for patients with a poor prognosis, i.e. those with anemia and/or thrombocytopenia prior to treatment. A median survival of 55 months for the 40 Stage III-IV patients is 2-3 times longer than described for comparable patients in other series. This experience indicates TBI may be the most effective single agent" available for the treatment of CLL and warrants consideration in primary therapy. © 1979."