In order to investigate the potential susceptibility of bone marrow stromal myoid cells to human immunodeficiency virus (HIV), a myoid cell population devoid of all other cellular components of marrow environment was isolated from 3 normal adult bone marrow samples. The bone marrow myoid cells were infected with 3 different strains of HIV-1, 2 strains isolated from patients with acquired immune deficiency syndrome (AIDS) and HTLV-IIIB strain. To demonstrate successful infection and HIV production, culture supernatants, harvested weekly until 2 months post-infection, were tested for the presence of p24 antigen and infectious virus. Myoid cell monolayers obtained from the 3 different bone marrow samples were shown to be susceptible to infection. In particular, infection led to the presence of p24 antigen and of infectious virus in culture supernatants up to day 49 post-infection. After day 49, it was not possible to demonstrate the presence of infectious virus in culture supernatants and HIV-DNA polymerase chain reaction (PCR) failed to show viral genome in any of the cultures assayed. Our results demonstrate the susceptibility of myoid stromal cells to HIV infection and may provide an in vitro model for studying the effects of HIV infection in disregulation of the haemopoietic function of bone marrow environment.