Objective: To systematically review the literature evaluating the diagnostic accuracy of commonly used diagnostic tests over conventional history taking and physical examination in children ≤18 months and >18 months suspected of gastroesophageal reflux disease (GERD). Study design: We searched Medline, Embase, and the Cochrane database for studies assessing the diagnostic accuracy of pH-metry, pH-impedance, esophagogastroscopy, barium contrast study, scintigraphy, and empirical treatment as diagnostic tools. Quality was assessed according to Quality Assessment of Studies of Diagnostic Accuracy Included in Systematic Reviews criteria. Results: Of the 2178 studies found, 6 studies were included, containing 408 participants (age 1 month-13.6 years) and 145 controls (age 1 month-16.9 years). Studies included children with GERD symptoms; 1 included an atypical presentation. In all the studies, the diagnostic accuracy of pH-metry was investigated, and in 2 studies esophagogastroscopy was investigated as well. Sensitivity and specificity were calculated in 3 studies. The range of reported sensitivity and specificity was broad and unreliable because of poor methodological quality according to Quality Assessment of Studies of Diagnostic Accuracy Included in Systematic Reviews criteria and inadequate study design. Conclusion: Diagnostic accuracy of tests in children suspected of GERD remains unclear and implications for practice are hard to give. There is an urgent need of well-designed randomized controlled trials where the effect of treatment according to specific signs and symptoms will be compared with the effect of treatment based on the results of additional diagnostic tests, for patient relevant outcomes. © Copyright 2013 Mosby Inc. All rights reserved.