Purpose: EUGR in preterm infants is a major problem in NICUs and is related to long-term growth deficit and neurodevelopmental outcome. The aim of this study was to determine the frequency and risk factors of EUGR and to discuss modifiable risk factors. Material and Methods: The study subjects consisted of 125 preterm VLBW infants with a gestational age ≤32 weeks who were born in Seoul National University Children’s Hospital NICU between Nov. 2005 and May 2009. Infants were classified as EUGR (10th percentile) or non-EUGR based on weight for gestation at hospital discharge. Results: The incidence of EUGR was 65.2% (n=82), while the incidence of IUGR was 32% (n=40). Birth weight, IUGR, duration of mechanical ventilation/symptomatic ileus/TPN, time to full feeding, day 14/21/28 feeding volume/kg, average daily weight gain during the first 28 days were significant predictors of EUGR. By multiple logistic regression, presence of IUGR was the greatest predictor of EUGR, and average daily weight gain during the first 28 days was independent predictor of EUGR. Risk factors for EUGR in non-IUGR infants were evaluated because 55.3% (47/85) of non-IUGR infants developed EUGR at discharge. Small head circumference, RDS, duration of symptomatic ileus/antibiotics, time to full feeding, d14/21/28 feeding volume, average daily weight gain during the first 28 days were significant predictors of EUGR. By multiple logistic regression, head circumference percentile at birth was the greatest predictor and average daily weight gain during the first 28 days was also independent predictor of EUGR in non-IUGR infants. When analyzing risk factors for average weight gain under 10g/day during the first 28 days, BPD severity, PDA ligation, duration of NPO/TPN/antibiotics, maximal weight loss, initial feeding day were predictive factors and gestational age was an independent predictor for poor weight gain during the first 28days. Conclusion: EUGR was significantly prevalent in NICU. IUGR was the most predictive factor for EUGR. Half of non-IUGR infants also developed EUGR and poor weight gain during the first 28 days was an important predictor. This results support the importance of early nutritional intervention for the weight gain during the first 28 days which have lagged behind other modern therapeutic interventions when the infant is clinically unstable.