The child with abdominal distention can be a formidable clinical challenge. The number of possible diagnoses is large, and the most likely diagnosis varies greatly with the child's age. Furthermore, not all distention is pathological. Healthy infants may have variable degrees of abdominal distention caused by aerophagia during feeding or crying or from transient constipation; healthy toddlers have a potbelly resulting from a combination of lumbar lordosis and hypotonia of the abdominal rectus muscles. The nonpathological distention often seen in infants and toddlers may exceed the mild distention seen with some intraabdominal malignancies. Thus, not surprisingly, numerous cautionary tales exist of parents being reassured by a physician that a child's mild and otherwise asymptomatic abdominal distention was normal, only later to learn that it was a tumor. Therefore a careful systematic approach should be used whenever concerns about abdominal distention are raised.