The objective of this research was to determine the oxygen consumption of newborn infants with respiratory distress syndrome in the first 4 days of life. Serial determinations of oxygen consumption were made in 14 infants with respiratory distress syndrome receiving positive end-expiratory pressures. The mean (+/- SE) oxygen consumption determined at 24, 48, 72, and 96 h postnatal age were 8.3 +/- 0.9, 6.5 +/- 0.8, 5.5 +/- 0.5, and 5.3 +/- 0.6 ml/min/kg, respectively. The level of oxygen consumption at 24 h postnatal age was significantly greater than the levels determined at 48, 72, and 96 h (p less than 0.03). The oxygen levels found at 72 and 96 h of age were comparable to those determined for healthy preterm infants. A linear regression of serial oxygen consumption and weight loss yielded a 'fair' (r = 0.5) correlation with a significant inference (p less than 0.01).