Caring for children with gastrointestinal motility disorders requires an understanding of age-related changes in gastrointestinal function and in the clinical expression of disease. Successful evaluation of the child with a gastrointestinal motility disorder necessitates an approach that takes into account not only the child's symptoms, but also the stage of development. This article reviews the ontogeny of gastrointestinal motility; the techniques available for the study of gastrointestinal motility in children; and the presentation, pathophysiology, and treatment of pediatric functional bowel diseases. Differences in children compared to adults in performing and analyzing motility testing and in evaluating motility disorders are emphasized. A more complete understanding of pediatric motility disorders may provide important insights in approaching functional bowel diseases in adults.