Four asymptomatic homosexual men reverted from positive to negative serologic results for the human immunodeficiency virus, type 1 (HIV-1) over 2.5 years, as shown by enzyme-linked immunosorbent assay (ELISA) and Western blot. Antibody bands in the Western blot from three men were undetectable 6 to 12 months after being positive; gradual fading of the number and intensity of bands was seen in the other man. No HIV-1-p24 antigenemia was detected; cryopreserved peripheral blood mononuclear cells were negative for HIV-1 by standard culture assay. Polymerase chain reaction (gene amplification) assays were done on peripheral blood mononuclear cells and showed the HIV-1 provirus in all subjects 6 to 18 months after the last positive antibody test. Serum specimens from each participant were genetically identical. Polymerase chain reaction showed that peripheral blood mononuclear cells from one subject at different times matched by HLA DNA typing. Clinical and laboratory features of these four men were similar to those of other seronegative subjects. Rare, asymptomatic persons seropositive for HIV-1 may not remain seropositive, but may remain latently infected with HIV-1.