We retrospectively evaluated the outcome and the risk factors for mortality among extremely low birth weight (ELBW) infants born at National Taiwan University Hospital. The records of all live-born infants with body birth weight of less than 1,000 g from January 1, 1993, to December 31, 1996, were evaluated. Infants with major anomalies or whose parents refused resuscitation were excluded from the analysis. There were 81 ELBW infants (0.59%) among a total of 13,835 live births during the study period, and 73 cases were enrolled for study. The mean gestational age (GA) was 27.2 (range, 24-34) weeks. Sixty-six percent of the ELBW infants were born by cesarean delivery. Respiratory distress syndrome occurred in 64% of infants and exogenous surfactant therapy was given to 47%, while intermittent mandatory ventilation was given to 85%. Symptomatic patent ductus arteriosus occurred in 34% of infants, septicemia in 30%, chronic lung disease in 48%, grade III to IV intraventricular hemorrhage in 27%, stage III to V retinopathy of prematurity in 33%, and necrotizing enterocolitis in 8%. Neonatal survival was 74%, survival to discharge was 60%, and intact survival was 50%. The survival rate was 40% for infants with a birth body of weight less than or equal to 750 g, and 68% for those with a birth body weight of greater than 750 g. While survival was 27% for infants with a GA of less than 26 weeks, it was 75% for those with a GA of greater than or equal to 26 weeks. The survival rate improved year by year for those with a GA less than 28 weeks. Cox regression analysis of survival showed that Apgar score at 1 minute (p = 0.0063), pulmonary hypertension (p = 0.012), and severe intraventricular hemorrhage (p = 0.0031) were the most important factors associated with mortality. Though the outcome of ELBW infants in our institute seems poorer than in some more developed countries, it is improving. The prognosis for ELBW infants of 24 to 25 weeks' GA remains guarded under our present care.