Pediatric human immunodeficiency virus (HIV) infection is a disease of mother-to-infant transmission. The World Health Organization estimates there will be ten million HIV-infected children by the end of this century. It is now thought that both intrauterine and intrapartum transmission of HIV occurs. Infants infected in utero develop clinical signs and symptoms at an earlier age than those who are infected at the time of delivery. We describe two cases that demonstrate early-onset and late-onset pediatric HIV disease, respectively. Recently, it was determined that perinatal transmission of HIV can be significantly reduced by the administration of the antiretroviral drug, zidovudine (ZDV), to HIV-positive pregnant women and their newborns, making HIV screening of pregnant women more desirable than ever. A program of universal voluntary HIV testing for pregnant women has been successfully implemented at the University of Arkansas for Medical Sciences. Details of this program are described herein.