OBJECTIVE:The presence of eosinophils on esophageal biopsy is a marker of esophagitis in children. Eosinophilic inflammation without evidence of gastroesophageal reflux has led to the new diagnosis of eosinophilic, or allergic, esophagitis. The aim of this study was to correlate the number of eosinophils with the reflux index on same day esophageal biopsy and 24 h esophageal pH monitoring.METHODS:A retrospective analysis of data collected from children who underwent same day endoscopy with esophageal biopsies and 24 h esophageal pH monitoring over a 3-yr period was performed. The patients were divided into five groups: Group 1: 0 eosinophils/hpf and no histologic change, Group 2: 0 eosinophils/hpf but histologic changes, Group 3: 1–5 eosinophils/hpf, Group 4: 6–20 eosinophils/hpf, and Group 5: >20 eosinophils/hpf. Reflux indices were analyzed within each group.RESULTS:A total of 305 patients met the inclusion criteria. The mean reflux indices ± standard error within each group were Group 1 (n = 171): 2.14 ± 0.18%, Group 2 (n = 40): 3.93 ± 1.24%, Group 3 (n = 42): 5.96 ± 1.53%, Group 4 (n = 21): 4.18 ± 1.27%, and Group 5 (n = 31): 2.02 ± 0.53%. The mean reflux index in Group 3 was significantly greater than Groups 1 and 5.CONCLUSIONS:The presence of denser infiltrates of eosinophils does not correlate with increased gastroesophageal reflux. The finding of more than 20 eosinophils/hpf is likely associated with a normal reflux index and a nonacid-related cause of esophagitis.