The aim of the present study was to evaluate changes in body composition in 48 preterm infants in relation to protein and energy intakes from term up to 3 months of corrected age, using air displacement plethysmography. Protein intake (grams per kilogram per day) was negatively associated with percentage of fat mass at 1 month of corrected age. The high-protein-intake group showed greater gain in lean body mass gain than did the low-protein-intake group. This finding suggests that during the first month of corrected age, high protein intake results in a significantly different weight gain composition.