We conducted a clinical trial to assess whether surfactant-TA given within the first six hours of life could improve oxygenation and reduce the ventilatory support in premature infants with hyaline membrane disease (HMD) during the first 24 hours of life. Eight premature infants with severe HMD requiring ventilation were treated, at a mean age of 2.72 hours, with a single intratracheal instillation of surfactant-TA (120 mg/kg). Arterial oxygenation improved dramatically as reflected by the increase of the a/A PO₂ ratio and PaO₂ to about 2 times the pretreatment values within 3 hours after surfactant treatment. And thus, oxygen concentrations (FiO₂) could be reduced and remained significantly lower than pretreatment values during the first 24 hours after treatment. Infants given surfactant-TA required lower mean airway pressure (MAP) and had a significantly decreased ventilatory index (VI) during the first 24 hours after treatment, which reflect the decreased requirement for ventilatory support. Chest radiograph scores significantly improved within 24 hours after treatment compared with pretreatment scores. In this trial, we found that a single intratracheal dose of surfactant-TA given to infants with HMD resulted in improved respiratory status and radiographic findings during the first 24 hours after treatment.