Dehydroepiandrosterone (DHEA) is a steroid hormone produced by the adrenal cortex that serves as an intermediary in sex steroid synthesis. DHEA is produced in abundance by humans and most other warm-blooded animals. Based upon previous reports demonstrating the antiviral and immunostimulatory activities of DHEA and DHEA-sulfate (DHEAS) we sought to determine whether introduction of these compounds would affect replication of feline immunodeficiency virus (FIV) in chronically infected cells. When cell number, cell viability, cellular DNA synthesis, and levels of FIV reverse-transcriptase (RT) were measured in cell cultures treated with various dilutions of DHEA or DHEAS it was found that the production of FIV RT was inhibited by DHEA at levels where cellular viability and DNA synthesis were not affected. At the concentrations tested DHEAS did not inhibit FIV replication or impact on cellular viability or proliferation.