The main role of ultrasonography of the esophagus in children is to exclude gastro-esophageal reflux. This technique can be used in patients with chronic ENT and/or respiratory tract infections. If US is positive, medical treatment can be instituted. Other causes such as allergy or immune deficiency must be investigated whenever US remains negative. Since US allows a poor assessment of the severity of reflux, it is not recommended in clinically obvious GER. US is also not very sensitive for esophagitis. A detailed study of the anatomy and dynamics of the esophagus and stomach can be performed, but such studies have no value as a first-line examination. Whenever reflux persists despite medical treatment, US can be proposed to look for hiatus hernia.