Many public health and social issues relate to infection with the human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV)-the virus that causes the acquired immunodeficiency syndrome. One such issue is the care and education of infected children, both in schools and in day care facilities. To date, transmission of HTLV-III/LAV in either the school or the day care setting has not been documented. However, because the virus has been isolated from a variety of body fluids, contact with such fluids from an infected child poses at least a theoretical risk of transmission. Past experience with transmission of hepatitis B virus provides a possible model to aid in understanding the epidemiology of HTLV-III/LAV infection. The risk of transmission of HTLV-III/LAV in day care settings is not known, and infection with this virus carries serious public health and clinical implications.