Ultrasound is a new test proven to be sensitive in the demonstration of gastroesophageal reflux (GER). Following reflux seen with ultrasound various symptoms can be observed in physiological circumstances, and thereby a causal relationship between reflux and these symptoms can be observed in physiological circumstances, and thereby a causal relationship between reflux and these symptoms can be proven. We performed a study in 220 children suspected of GER to determine the incidence of sonographically demonstrated "" in different clinical groups: children with (1) vomiting only, (2) respiratory symptoms, (3) attack-like symptoms, and (4) pain and irritability. Overall, GER was demonstrated in 78% of all 209 children in whom technically satisfactory studies could be performed. This reflux was associated with symptoms in 32% of the cases. Symptomatic reflux was most frequent in group 3, which included children investigated for near-miss sudden infant death syndrome. The symptoms that were noted most frequently were vomiting, motor unrest, coughing, and wheezing. Apnea, bradycardia and attacks of unusual posturing could incidentally be related to reflux. Ultrasound is a cheap, simple, noninvasive, and physiological test to show clinically significant reflux.