Currently there is considerable evidence showing that the GIT and other mucosal tissue, and not the blood, are the main site of HIV infection and CD4 + T cell loss. Earlier the pathogenesis of HIV infection has mostly been centered on mucosal viral “target” cells. In this personal view we summarize recent findings related to the role of bacteria and yeasts in the etiopathology of AIDS. Data are presented showing detection of HIV-like sequences and HIV-like proteins in bacteria and yeasts of HIV positive patients from the USA, Slovakia, Kenya and Kambodia. This pioneer view of AIDS etiopathology suggests that the aforementioned microbes bearing HIV genetic information would play an important, if not a key role, in the immunodeficiency process.