The early childhood years provide an important window of opportunity to build a strong foundation for future development. The newborn’s skills and abilities increase rapidly in a secure, stimulating environment, with supportive interactions and adequate nutrition. These environmental conditions, however, are not in place for millions of young children living in underprivileged conditions in poorer countries, putting them at risk for suboptimal development. The urgent need for early child development support has been widely acknowledged, but one impediment to global progress is the lack of a population-based measurement framework for children under 3 years of age that can provide reliable estimates of developmental status. This case study describes the feasibility phase of a program of work to create the World Health Organization Infant and Young Child Development assessment tool for use in surveillance monitoring and as an outcome measure in intervention studies.