Extensive research has shown comprehensive early interventions can improve the developmental outcomes of disadvantaged children. However, the evidence on the effectiveness of high-quality center-based programs for young children in developing countries is still scarce, where programs are typically of low quality and only short-term impacts have been assessed. This paper reports short and medium-run effects from a high-quality early education intervention characterized by key elements of process quality such as project and play-based learning and rich adult-child interactions, on children younger than four years of age in two communities in northern Colombia. We find strong positive effects on cognitive development and health, and no significant impacts on socioemotional development.