Down syndrome (DS) is the most common chromosomal cause of developmental disability in Ireland. Children with DS have a high incidence of associated treatable medical disorders where early intervention carries a better outcome. Currently there are no agreed protocols for the screening and management of children and adults with DS in Ireland. A cross-sectional study of 394 children and adolescents was undertaken in the Eastern Regional Health Authority (ERHA) to assess the medical needs of children and adolescents with DS, in order to develop medical management guidelines. This study provides evidence-based data that children and adolescents with DS have a high incidence of treatable medical disorders, which supports the need for the medical management guidelines presented.