Thanks to very effective interventions vertical transmission of HIV has been reduced from over 20% ten years ago to less than 2% today in industrialised countries. This progress has been achieved by combined application of different strategies including antiretroviral treatment of pregnant women, elective caesarian section (prior to labour and rupture of membranes) and refraining from breastfeeding. Fortunately, the Swiss Mother & Child HIV Cohort Study (MoCHiV) has been able to support this evolution with several important contributions. Nevertheless the most important challenge in the prevention of vertical HIV transmission remains to be resolved in this decade. This impressive reduction in vertical transmission achieved in the industrialised world and delineated in this article still needs to be carried forward to those countries in the third world where HIV prevalence is much higher and interventions therefore much more needed.