We have studied the natural history of the acquired immune deficiency syndrome (AIDS), and the part that irradiation plays in the management of this devastating and fatal disease. The radioresponsiveness of the two most common malignancies associated with AIDS, Kaposi's sarcoma (KS) and malignant lymphoma (ML), has been demonstrated. We have documented satisfactory time-dose relationships for the management of multiple manifestations of KS, including cutaneous and deep subcutaneous extremity involvement, visceral lesions, and AIDS-associated lymphadenopathy. A similar time-dose construct has been documented for ML, involving the brain and both central and peripheral lymph nodes. Irradiation can provide good to excellent palliation with only minimal side effects, and will produce a lesser impact on the hematological and immunological systems than chemotherapy. Therefore, we advocate the liberal employment of palliative radiation therapy in patients with AIDS.