BACKGROUND: Both the i-gel(TM) (i-gel) and LMA Supreme(TM) (Supreme) are new single-use second generation supraglottic airway devices available in pediatric sizes. This study was designed to investigate the i-gel in comparison with the Supreme in children undergoing general anesthesia. METHODS: One hundred children with American Society of Anesthesiologists physical status I or II undergoing general anesthesia were randomly assigned to either the i-gel or the Supreme group (50 children in each group). The device size was chosen according to weight of the children. We assessed the insertion success rate, insertion time, oropharyngeal leak pressure, grade of the fiberoptic glottic view, number of airway manipulations required, and postoperative complications. RESULTS: There were no differences in the demographic data between the two groups. The success rate of insertion was same in both groups. The insertion time of the i-gel was longer than that of Supreme (P = 0.004). The oropharyngeal leak pressure in the i-gel group was higher than that in the Supreme group (P = 0.013). On fiberoptic examination, the vocal cords were visible in 90% of the children in the i-gel group and in 96% of the children in the Supreme group. The number of airway manipulations required was higher in the i-gel group (14 cases) than in the Supreme group (1 case) (P < 0.001). There were no differences in complications including blood staining of the device and sore throat between both groups. CONCLUSIONS: Both the i-gel and Supreme provided a satisfactory airway during general anesthesia in children. Compared to the Supreme, the i-gel demonstrated a higher oropharyngeal leak pressure, longer time for insertion, and a greater number of airway manipulations during anesthesia.