In this study we use longitudinal data from Chile to estimate the effects on child cognitive and socioemotional development from participation in public child care centers targeting low-income populations. We implement empirical approaches, which allow for heterogeneous treatment effects and endogenous selection into child care. A major expansion of public child care provision enhances our identification strategy. We find significant positive incremental effects in the area of emotional regulation but potentially severe negative incremental effects on child-adult interactions. These findings confirm the benefits of early childhood education but raise awareness on the importance of securing quality when increasing coverage.