AZT is the only antiviral agent with demonstrated effectiveness in patients with severe HIV infection. Persons with HIV infection may have additional health problems, one of which is a diseased kidney due to infection of the kidney, or side effects of therapy. The benefits and risks of AZT in patients with diseased kidneys are unknown. It is hoped that this study will allow further understanding of the metabolism and excretion of AZT in patients with kidney disease. AZT pharmacokinetics will be studied in patients with mild, moderate, and severe renal disorders