PURPOSE: This study was undertaken to determine the comparative efficacy between Surfacten and Newfacten in the early course of respiratory distress syndrome, ventilatory parameters, mortality and complications of RDS. METHODS: For the period of March 1998 to August 1999, total 60 neonates with RDS were treated with Surfacten (n=30) or Newfacten (n=30) at 2 different hospitals. Patients were enrolled for the trial if the following criteria were met; (1) age less than 24 hours; (2) birth weight between 800 gm and 2,500 gm; (3) clinical and radiographic findings consistent with RDS; (4) respiratory distress severe enough to require endotracheal intubation and mechanical ventilation; (5) a written informed consent by a parent. Infants were not eligible if they had a congenital anomaly or proven chromosomal anomaly. Two groups were treated with the equal doses of Surfacten and Newfacten via identical method and the various ventilator parameters, mortality and complications of RDS were compared. RESULTS: Surfacten was administered at 5.8 5.5 hour after birth and Newfacten was administered at 5.9 5.4 hour after birth. There were no differences in birth weight, gestational age in between 2 study groups. Ventilator parameters such as FiO2, MAP, VI, a/APO2 were measured in both groups and the differences were not statistically significant. There were no differences in the incidence of BPD, PDA, IVH, NEC, pneumothorax, pulmonary hemorrhage and ROP between two groups. There were no differences in mortality, the duration of ventilator care, and oxygen therapy between two groups. CONCLUSION: The effectiveness of Newfacten was comparable to that of Surfacten in terms of its efficacy in the treatment of RDS, complications, and mortality.