Despite an overall reduction of child mortality in LMICs, acutely-ill undernourished children continue to have a greatly elevated risk of death, both during hospitalisation and following discharge. However, we currently lack robust evidence for their management. Factors underlying the risks of mortality may relate to the acute illness itself, to children's longer term health trajectories, or to the home nutritional and care environment. The ultimate goal of the CHAIN Network is to identify and prioritize actionable intervention targets to reduce mortality among acutely ill undernourished children.