PURPOSE:Factors influencing postnatal growth are innumerable. It is known that genetic factors such as parental height and environmental factors such as nutrition, economic status and hormonal effects are important factors. The purpose of this study was to examine the factors affecting final adult height in normal children. METHODS:753 high school students (513 boys, 240 girls) who live in Seoul were studied. Height and body weight were measured and questionaires about sexual development were examined. We included the subjects who reached fianl adult height. The criteria of final adult height was as following: ages over 17 years in the boys and over 15 years in the girls and growth velocity was less than 1 cm per year. They had no systemic diseases and height standard deviation scores were more than -2.5. RESULTS: 1)Final adult heights were 173.1+/-.1cm in boys and 160.9+/-.7cm in girls. 2)Final adult height significantly correlated with father height(r=0.13, p<0.01), mother height(r=0.25, p<0.01), midparental height(r=0.25 p<0.01) and birth weight (r=0.16, p<0.01). 3)In short final adult height groups, birth weight and midparental height were significantly lower(p<0.05), but puberty onset age, body mass index and economic status were similar to normal stature groups. 4)Final adult height significantly correlated with target height.(r=0.43, p<0.01). In boys, the final adult height was 1.7cm taller than target height on the average. In girls, final adult height was 1.6cm taller than target height on the average. 5)In the group in which final adult height is less than target height, birth weights were significantly lower than those of the groups in which final height is greater than target height. CONCLUSIONS:Among factors affecting final adult height, parent height and birth weight were important. To predict final adult height, target height can be used simply and target height showed significant correlation with final adult height. In the case of showing differences between final adult height and target height, many factors including birth weight will influence the outcome.