Background & Aims: The aim of the present study was to find whether prone position is one of the symptoms of childhood gastroesophageal reflux disease or not. Method: In this prospective case-control study, 200 children with gastroesophgeal reflux disease (case group) and 210 healthy children (control group) were studied between 21 march 2009 and 21 march 2011. Data gathering was performed by a questionnaire including variables of sex, age, main complaint, sleeping position, endoscopic and pathologic findings. The questionnaires were filled out by face to face interviews with children’s mothers. The patient group underwent upper endoscopy with pediatric video-endoscope. Pathologic reflux was approved in histological studies. Results: Mean age of case and control groups were 5.0 ± 3.2, and 5.2±3.0 years respectively. The most common symptoms were abdominal pain (46.5%), and vomiting (34.8%). The majority of cases with esophagitis (73%) lied in prone position in night that had significant difference (P<0.0001) with the corresponding value in the control group (37.1%). In present study sensitivity and specificity of prone position for gastroesophagal reflux disease were respectively, 73% and 62.9%. Conclusion: According to the results, during taking history, prone position should be questioned.