PURPOSE: To assess the usefulness of multi-detector CT (MDCT) with multiplanar reformations (MPR) for the evaluation of the position, diameter and presence or absence of intraluminal gas in the normal appendix in children. MATERIALS AND METHODS: From 2007 to 2010, we retrospectively analyzed the MDCT images of normal appendices in 133 children, and evaluated the position, diameter, and presence or absence of intraluminal gas in the appendix. RESULTS: Among the 133 appendices, type I (postileal and medial paracecal position) was found in 64 children, type II (subcecal position) in 22, type III (retrocecal and retrocolic/laterocolic position) in 15, type IV (preileal and medial colic position) in 16, and type V (lower pelvic position) in 16 children. The mean diameter was 5.8 mm +/- 1.2 (SD) (range; 3.2-8.7 mm). There was a high correlation between the appendiceal diameter and age (p = 0.000).There was no statistically significant difference in the appendiceal diameter between boys and girls (p = 0.470). Intraluminal gas was found in 115 appendices and there was no statistically significant correlation between the appendiceal diameter and intraluminal gas (p = 0.502). CONCLUSION: The MDCT with MPR was useful for the evaluation of the normal appendices in children. The procedure may be useful for the diagnosis of equivocal or unusual appendicitis in children.