The purpose of this article is to review ultrasonographic appearance of the most common causes of non-traumatic acute abdominal pain in pediatric patients and to understand the applications and limitations of this technique giving a practical approach showing different clinical cases. A pictorial review of cases was made presenting the most common causes of neonatal and pediatric non-traumatic acute abdominal pain; sonographic features are discussed. Ultrasound in conjunction with Color Doppler imaging is a valuable tool in the evaluation of neonatal and pediatric non-traumatic acute abdominal pain; causes of acute abdomen in children could vary depending on the ages of the children.