BACKGROUND Wide variation exists in the treatment of suspected gastroesophageal reflux disease (GERD) in premature infants; it is unknown to what degree diagnosis and treatment are affected by the treating physician's medical specialty or interpretation of the medical literature. METHODS This study involved an online survey of board-certified neonatologists, pediatric pulmonologists, and pediatric gastroenterologists about their beliefs regarding the symptoms, diagnosis, and treatment of GERD in premature infants in the NICU on the basis of both clinical impression and interpretation of the literature. RESULTS A total of 1021 neonatologists, 232 pediatric pulmonologists, and 222 pediatric gastroenterologists participated in the study (47.5% response rate). There was disagreement among specialists in nearly all aspects of the survey. Pulmonologists were most likely to report that respiratory symptoms are caused by GERD (P < .001). Neonatologists were least likely to report that a therapeutic trial of pharmacologic agents would be useful for diagnosing GERD (P < .001) or that lansoprazole, ranitidine, or cimetidine are safe or effective (P < .001). No pharmacologic therapy had >50% of respondents supporting its effectiveness. There was moderate correlation between physician belief based on the medical literature and belief based on clinical impression (Spearman rank correlation: 0.47-0.75). For therapies supported by multiple meta-analyses in infants versus therapies with few infant trials, physicians rated the evidence for effectiveness similarly. CONCLUSIONS There is wide variation among pediatric specialists regarding beliefs about GERD in premature infants, as well as about the weight of evidence in the medical literature for this patient population. Physician beliefs do not seem to be driven by the degree of evidence in the neonatal literature. With no agreed-on standard of care in the setting of widespread use of antireflux medications, greater understanding is needed about the ways physicians form clinical impressions, access and process medical evidence, and apply it to patient care.