The frequency and clinical significance of gastroesophageal reflux (GER) in patients after percutaneous endoscopic gastrostomy (PEG) was determined. Ten children, aged 11 months to 15 years, who had normal preoperative extended esophageal pH monitoring were restudied after PEG. Of the ten patients, six developed GER with a pH score significantly higher than their initial one (40.5 +/- 3.3 pre-PEG v 129.5 +/- 24.2 post-PEG, P less than .005). Similarly, the mean post-PEG pH score was higher in patients with GER than in those without a change in score (129.5 +/- 24.2 v 33.8 +/- 2.8, P less than .005). None of these patients was symptomatic for GER immediately after the PEG, but within 10 months of surgery, three of six (50%) developed reflux-related symptoms. These data indicate that clinically significant GER is associated with PEG.