Recent reports indicate that nasoduodenal feeding is a suitable technique for high risk newborns, in particular those with a low birth weight. In the period between February 1975 and June 1976, 100 high risk newborns, divided into four cohorts on the basis of birth weight in 500 g divisions, were fed by nasoduodenal tube. The effect of nasoduodenal feeding has been measured in several ways, but particularly consideration has been given to weight gain, its caloric cost, the mortality rates observed in the Unit before and after the introduction of this nutritional regime and complications. The use of nasoduodenal feeding abolished the physiological loss of weight which normally occurs during the first week of life and was associated with a subsequent rate of weight gain equal to or better than that observed in infants fed by other routes. The mean caloric intake was greater in smaller infants than in larger ones and it was accompanied by a steady decrease in weight gain per unit of caloric intake with increasing birth weight. In 1974 the overall mortality rate in the Unit was 18% and in 1975 following the introduction of nasoduodenal feeding fell to 11.4%. No serious complications were observed associated with nasoduodenal feeding. The conclusion is that this form of feeding is particularly suitable for infants with a birth weight of 1 500 g or less.