Evaluación del Desarrollo Infantil or Child Development Evaluation (CDE) test, a screening tool designed and validated in Mexico, classifies child development as normal (green) or abnormal (developmental lag or yellow and risk of delay or red). Population-based results of child development level with this tool are not known. The objective of this work was to evaluate the developmental level of children aged 1-59 months living in poverty (PROSPERA program beneficiaries) through application of the CDE test. CDE tests were applied by specifically trained and standardized personnel to children