Here we describe the KIR and HLA gene content among several mother-infant HIV-1 cohorts, in order to investigate if KIR genes and/or KIR genes together with their known HLA ligands may play a role in susceptibility of infants to HIV-1 infection and/or in modulating the risk of maternal HIV-1 transmission to the infant. Here, KIR3DL1 is linked to HIV-1 infection.