Background: Undiagnosed children with neurodevelopment delay disorders (NDD) frequently experience school difficulties, leading to school desertion or academic failure with subsequent familial, social and work-related problems. Methods: In 2004-2005, we conducted a cross-sectional study to determine the prevalence of developmental delay among preschoolers in Bogotá (Colombia); convenience samples in several socioeconomic areas of the city were screened to define the prevalence of NDD. Parents and teachers were interviewed to identify children with possible NDD. Selected children were evaluated with a neurodevelopmental abbreviated scale (EAD-1). Results: We screened 2,043 preschool children aged