Understanding the Early Years in Montreal is an initiative that is part of the national aid program for child development and the fight against poverty. Still in progress, this study uses three sources of information with the goal of understanding the developmental level of children in some areas of Montréal when they start school. Kindergarten teachers from 28 public schools first evaluated the degree of preparation for school these children had. The parents supplied information on their general development. Finally, the characteristics of the populations and the resources available on the territory being studied were examined. The results of this collection of data were shared with community stakeholders to enrich the programs and the resources available to children and families. The article describes the origins of the national project, the results of the evaluation of these children’s preparedness for school and the socio-economic characteristics of the populations being studied. The article concludes with a description of the knowledge transfer activities with partner organizations from the perspective of a revision of local early childhood action plans.