During a 24-hour interval, examination was carried out of 5 full-term and 4 preterm newborns in whom no disturbance of postnatal adaptation was found. The newborns received parenteral nutrition using infusates containing 20% Intralipid during 7 hours on the average. The mean daily dose of Intralipid was 1.2 g/kg, infusion rate was 0.17 g/kg/h. The concentration of FFA (n = 9) and ABC/Bi was examined three times in the course of 24 hours, and that prior to Intralipid administration, after one-hour infusion, and approximately 17 hours after the end of infusion. Before infusion and 24 hours after the first collection, blood bilirubin and glucose concentrations, and the values of pH, pCO2 and BE (= 9) were examined. One hour after the start of Intralipid infusion the mean FFA concentration was reduced and decreased again during the following 23 hours. The differences were mostly insignificant. One hour after the start of infusion the mean value of the ABC/Bi ratio decreased insignificantly, but returned to the initial value by the end of the follow-up period (24 hours). The mean concentration of bilirubin and blood glucose and the values of pH, pCO2 and BE did not change significantly. It may be reasonably assumed, that in newborns showing normal postnatal adaptation in the first days of life, the administration of 20% Intralipid (as parenteral nutrition) exerts no substantial effect on the plasma FFA concentration and ABC/Bi ratio in the course of 24 hours. General principles for the indication of parenteral Intralipid administration to the newborn are given.