PURPOSE: The aim of this study was to analyze the correlation of gestational age and birth weight with weight gain of very low birth weight infants(VLBWI) during their hospital stay. METHOD: This is a 5 year retrospective study of which data were collected through review of medical records. Subjects were 124 VLBW infants with a birth weight more than 1000g and less than 1500g who received neonatal intensive care at the university hospital between January 1, 1997 to December 31, 2001. RESULT: After calculating the z scores of birth weights and discharge weights, z scores of discharge weight and birth weight were compared with the median weight of a fetus of comparable gestational age based on an intrauterine growth reference. There was a significant difference between z scores of birth weight and discharge weight(t=11.60, df=122, p=0.000). Regardless of intensive care during the prolonged hospital stay, VLBW infants showed slow growth rate compared with the median weight of a fetus of comparable gestational age. CONCLUSION: VLBW infants developed a poor velocity of weight gain during the prolonged hospital stay after birth. The development worsened during the period of physiological weight loss and regain, and they did not reach to comparable growth rate of normal fetus even at the time of discharge. This poor growth velocity of VLBW infants influence negatively for their future growth. Therefore nureses who work at the neonatal intensive care unit must develop an effective nursing intervention protocol to promote the velocity of weight gain and to conduct the parental educational sessions to emphasize the importance of weight gain for VLBW infants at home.