Secretory immunoglobulin A (slgA) antibodies of non-maternal origin are present in newborns and slgA to HIV-1 antigens has been detected in infected adults. In this study we investigated the presence of HIV-1-specific IgA in saliva from 41 children (aged 1 day-46 months) born to women at risk for HIV-1 infection. Saliva samples were assayed for HIV-1 antibodies with IgA-specific Western blot. The samples from 10 out of 11 children with subsequently proven infection, including one aged 6 months, demonstrated IgA antibodies to HIV-1 envelope antigens. Samples from infants under 15 months, who were born to infected mothers and subsequently shown to be uninfected, were slgA negative. Of the 12 children with continued indeterminate HIV-1 status, eight showed neither slgA nor serologic evidence of infection and four showed slgA antibodies. HIV-1-specific slgA was detectable before the age of 15 months and may prove to be valuable in the diagnosis of HIV-1 infection in infants.