PurposeWe aimed to compare the efficacy and safety of midazolam plus ketamine versus fentanyl plus propofol combination administered to children undergoing upper gastrointestinal endoscopy (UGE) and to determine the most appropriate sedation protocol.Materials and methodsThis prospective, randomized, single-blind study included patients between the ages of 4 and 17 years who underwent UGE for diagnostic purposes. Patients were divided randomly into groups A (midazolam–ketamine combination, n=119) and B (fentanyl plus propofol combination, n=119). The effectiveness of the sedation and complications during the procedure and recovery period were recorded.ResultsThe processes started without an additional dose of the drug for 118 patients (99.1%) in group A and for 101 patients (84.8%) in group B (P=0.001). The average dose of ketamine administered to the patients in group A was 1.03±0.15 mg/kg and the average dose of propofol administered to the patients in group B was 1.46±0.55 mg/kg. None of the patients stopped the endoscopic procedure in group A, but one patient (0.8%) had to discontinue the endoscopic procedure in group B. 27 patients in group A (22.7%) and 41 patients (34.5%) in group B developed complications during the procedure (P=0.044). The rate of complications during the recovery of group A (110 patients, 92.4%) was significantly higher than that in group B (48 patients, 40.3%) (P=0.001).ConclusionIn children, UGE procedures can be quite comfortable when using the midazolam–ketamine combination. However, adverse effects related to ketamine were observed during recovery.