Systemic non-Hodgkin's lymphoma and Kaposi's sarcoma occur in approximately 4% and 30% of patients with HIV infection, respectively. Single-agent or combination chemotherapy is often indicated for such patients. Combination chemotherapy produces a significant decrease in CD4 lymphocytes and significantly increases the risk of opportunistic infection. Supportive care should include prophylaxis against Pneumocystis carinii pneumonia and esophageal candidiasis. Herpes labialis frequently occurs, may be confused with chemotherapy-induced stomatitis, and it requires appropriate treatment and secondary prophylaxis once recognized. Antiretroviral therapy should be continued during chemotherapy, if possible, and should be selected based on the patient's prior antiretroviral exposure, the toxicity profile of the antiretroviral agent, the toxicity of the chemotherapy, and the potential for drug interaction. The use of hematopoietic growth factors as primary prophylaxis may be reasonable for patients at high risk for febrile neutropenia, although the information about their use in this population is limited.