The aim of this study is to investigate if nasogastric feeding may provide an adequate caloric intake and a good growth in preterm infants. One hundred and thirty-one newborns with gestational age less than or equal to 33 weeks, admitted to the Neonatal Unit of the Catholic University of Rome over a period of three years, were included in the study. Infants were divided according to birth weight in four groups: the first includes 22 neonates weighing less than or equal to 1000 g; the second 60 newborns with birth weight of 1001-1500 g; the third includes 36 prematures weighing 1501-2000 g; the fourth group 19 neonates with birth weight greater than 2000 grams. Body weight was measured daily and head circumference weekly for all the study period (60-90 days). Mean postnatal weight loss was greater in the lowest birth weight group (13.2% of the birth weight) as compared to the other three groups (8%-9%). Birth weight was regained at 18th day of age in the newborns of the first group and in the second week of age in the other three groups. A caloric intake greater than 100 Kcal/Kg/day was achieved in the second week, ranging between the 8th day (forth group) and 14th day (first group). The achievement of full enteral feeding was inversely related to the birth weight.(ABSTRACT TRUNCATED AT 250 WORDS)