Purpose: Gastro esophageal reflux disease (GERD) is a burdensome disease affecting many children. A clinical examination is reported to be unreliable to diagnose GERD in children.This study aimed to investigate the relationship between the Pediatric Gastroesophageal Reflux Disease Symptom and Quality of Life Questionnaire (PGSQ) and endoscopic and histopathological findings in children with symptoms suggesting GERD. Changes in the PGSQ score in children with esophagitis as response to one month therapy were recorded as secondary outcome. Methods: This is a prospective cohort study in the pediatric outpatient clinic in an Indonesian tertiary hospital. Children aged 2–17 years old with clinical symptoms suspected of GERD are included in the study. Blinded endoscopic and histopathological examination was performed in all patients before one month proton pump inhibitors (PPI) therapy. The PGSQ information was collected at inclusion and after one month PPI treatment. Results: Fifty-eight subjects were included. Esophagitis was found in 60.9% of subjects according to endoscopy and 58.6% according to histology. There was no significant relationship between the PGSQ score and endoscopic (p=0.781) nor biopsy (p=0.740) examinations. The PGSQ showed a low diagnostic value compared to endoscopy and biopsy (area under the curve [AUC] 0.477, p=0.477, 95% confidence interval [CI] 0.326–0.629 and AUC 0.474, p=0.740 (95% CI 0.321–0.627 respectively). The PGSQ improved significantly post one month of PPI treatment. Conclusion The PGSQ cannot be used to diagnose esophagitis in children with clinical symptoms suggesting GERD. However, the PGSQ can be used to monitor the treatment response in children with esophagitis.