HIV infection is a complex model of mother-to-child transmission. Antiretroviral therapy can induce a dramatic reduction of the risk of transmission, actually the rate of transmission is about 1 to 2 % in France. The actual most important stake concerns the diagnosis and the follow up of infected women living in countries of high endemy where the programs are inappropriate at the moment. The knowledge of the mechanisms and the timing of HIV mother-to-child transmission need to be more developed in order to design adapted antiretroviral posology and to try to reduce infant's exposure to drug toxicity.