This study is designed as a prospective, observational and treatment study, with ongoing monitoring of the progression of HIV infection and HIV-related disease processes. A data base, not otherwise obtainable, will be collected of unusual disease processes related to HIV infection, and of the long-term effects of experimental treatments that patients may have received under earlier protocols for HIV and related infections. Up to 500 patients with known or suspected HIV-infection will be enrolled. Minimal studies scheduled for each visit will include monitoring of immune status, routine safety laboratory tests, and evaluation for possible opportunistic infections. Treatment plans will be individualized for each patient's particular condition, and the number and length of additional visits and diagnostic evaluations will vary accordingly. Specific treatment regimens will be in accordance with standard medical practice.