Colombia's national early childhood strategy launched in 2011 aimed at improving the quality of childcare services ofered to socio-economically vulnerable children, and included the possibility that children and their childcare providers could transfer from non-parental family daycare units to large chilcare centres in urban areas. This study seeks to understand whether the offer to transfer and the actual transfer from one programme to the other had an impact on child cognitive and socio-emotional development, and nutrition, using a cluster-randomised control trial with a sample of 2767 children between the ages of 6 and 60 months located in 14 cities in Colombia. The results indicate a negative effect of this initiative on cognitive development, a positive effect on nutrition, and no statistically significant effect of the internvetion on socio-emotional development. We also explored the extent to which these impacts might be explained by differences in the quality of both services during the transition, and report that quality indicators are low in both programmes but are significantly worse in centers compared to community nurseries.