Background: Improvement of nutritional intake by a concentrated and balanced nutritional supplement formula might have some positive effects on catch-up growth in children with growth faltering. The aim of this multicenter study is to evaluate the effect of nutritional supplementation with a pediatric nutritional formula ( Pediapowder®) on promoting growth and improving nutritional status in children with nonorganic growth faltering. Methods: Children aged 12 ~ 36 months whose body weight-for-age were below the 5th percentile on the Korean growth charts were enrolled prospectively for multicenter study under the consents from their parents. Children born premature or having apparent organic diseases were excluded. Children were instructed to consume 400mL of formula per day in addition to regular diet for 6 months. Pediatricians and dietitians educated the parents for nutritional intake every 2 month at each medical center. Anthropometric parameters were measured at baseline, 2, 4, and 6 months, and laboratory tests were done at baseline and 6 months in all study subjects. Good consumption group was defined as formula intake of ＞ 60% of the recommended dose and poor consumption group as intake of 60%. Results: Total 63 children completed the intervention. At baseline, there were no significant differences in all variables between the 2 groups. After 6 months of follow-up, all participants had a significant improvement in the levels of hematocrit, iron, TIBC, ferritin, and prealbumin (paired t-test, all P 0.05). The good consumption group significantly gained weight compared to the poor consumption group during the 6-month intervention period (independent t-test, P = 0.023). Height, head circumference, and mid-arm circumference had no significant differences between the 2 groups. The good consumption group revealed a significant trend for weight gaining for 6 months of formula intake compared to the poor consumption group ( P = 0.016 on GEE analysis). Conclusion: Nutritional supplementation with a concentrated and balanced pediatric nutritional formula along with dietary education might be an effective approach to promote catch-up growth in children with nonorganic growth faltering.