The purpose of the current research is to investigate the diagnostic value of ultrasonography of the pediatric gastroesophageal reflux disease. There were 29 children examined with clinical and endoscopic signs of gastroesophageal reflux in each of three age categories: less than 1 year, 1—6 years, and 7—14 years. The examination of abdominal esophagus, stomach and duodenum was conducted with the ultrasound scanner Ultrasonik. The abdominal esophagus was measured from its entrance into the diaphragm to the base of gastric folds. We also measured the diameter of esophagus, the width of lumen, thikness and structure of wall, and the His's angle. The most freqent symptoms of gastroesophageal reflux were the enlargement in diameter of esophagus and the thikening of abdominal esophagus wall, which were observed in 75,9% and 82,8% of cases correspondingly. It was noted that the enlargement of abdominal esophagus lumen happens on an empty stomach and after exercising in water in 44,8% of cases. 37,9% of children with gastroesophageal reflux have His's angle of 90 degrees. Gastroesophageal reflux was registered in 27,6% of cases. If children ranging in older age have enlargement in diameter of esophagus and the thikening of abdominal esophagus wall, it is the evidence of the incompetence of cardia and reflux esophagitis. Neonates with the syndrome of posseting are observed to have insignificant extention of abdominal part of esophagus (equal to 6—7 mm), it may be regarded as morphofunctional immaturity of lower esophagus sphincter.