Maternal and child under nutrition accounts for almost a third of all under 5 deaths globally and a large proportion of the long term disabilities and consequences. Much of the global burden of undernutrition exists in relatively few countries in Asia and Africa and is associated with poverty, high burden of disease and socio-cultural factors affecting dietary intake. Over the last few years rising food prices, global economic crisis and climate change have also emerged as major contributors to the burden of food insecurity and undernutrition. This is a compilation of articles reviewing the evidence base for maternal and child undernutrition and is intended for scholars and researchers interested in assessing the scientific basis for recommendations as well as gaps for further research. The chapters review some of the most important areas for interventions such as maternal undernutrition and micronutrient deficiencies, breastfeeding and complementary feeding as well as specific interventions related to key nutrients such as iodine, vitamin A, zinc and multiple micronutrients. In addition, large scale nutrition programs as well as financial support strategies are reviewed.