Down syndrome is the most frequent genetic cause of disability associated with development. The lack of normative values for these children, hinders an early assessment and monitoring of the clinical course. The objective was to describe the evolutionary profile of these children during the first three years of life. A prospective cohort study was performed, for 9 years, in which 156 children under 37 months were included. They had 528 evaluations by "Abbreviated Scale Development" (EAD -1), a valid and reliable standardized test in Colombia to assess the developmental level in children under 6 years. We obtained quarterly developmental quotients, percentile values, variations between the areas assessed, the evolutionary curve in each area studied and the most critical periods in different semesters. These values will enable monitoring the clinical course of these children, early identification of areas of greatest vulnerability and need for intervention, assessment of the impact of therapeutic interventions or programs of stimulation and guidance to parents and related health and social agents to development and survival of the boy and the girl. [ABSTRACT FROM AUTHOR]