Epidemic Kaposi's sarcoma, a neoplasm associated with AIDS, is rapidly becoming common in the United States and Europe. The pathogenesis of this form of Kaposi's sarcoma has not yet been fully understood, but epidemiological clues point to the possibility that an infectious agent (in addition to the AIDS virus HTLV-III) or an environmental toxin may be involved. The natural history and clinical course of epidemic Kaposi's sarcoma is variable. The life expectancy of an AIDS patient with Kaposi's sarcoma is probably related to his underlying immunologic status as evidenced by propensity to develop life-threatening opportunistic infections. Patients with this neoplasm should be entered on experimental treatment programs when possible in order to improve our knowledge about rational management of this disease. Recombinant interferon alfa-2a, single agent chemotherapy, and radiation all have roles in the management of the disease.