The aim of this study was to investigate the relationship between the appendiceal diameter (AD) and age, sex, height, and body weight in children and to verify how does the normal AD grows in childhood. We evaluated the AD of patients younger than 16 years of age who underwent laparoscopic surgery at our hospital. We statistically examined the relationship between the AD and the age, sex, height, and weight. A final cohort of 188 patients participated in the study. The median AD for the sample population was 5 mm (range, 3.2-8.1). There was no significant difference in the AD between males and females in the multivariate analysis (P = 0.500). There was a positive correlation between the age and the AD (R = 0.396, P < 0.001). The AD had a significant positive correlation with the height and weight (P < 0.001, P < 0.001, respectively). The reference curve with regard to the AD can be useful in clinical situations, although it should be kept in mind that the range of individual differences in AD is large, and the growth degree by age is not uniform during childhood.