Recent studies found a difference in body composition determined by skinfold thickness measurements between breast-fed and formula-fed infants in the first year of life. We therefore investigated the body composition of 79 infants at 12 months measured by total body electrical conductivity (TOBEC) and compared with early feeding mode (breast-feeding for at least 6 months versus formula-feeding or breast-feeding or for ≤2 months). Lower weight, stature and cranial circumference were associated with breast-feeding when the variables were compared using an ANOVA model. The groups did not significantly differ in terms of fat-free mass, but body-fat mass was lower among breast-fed infants. Multiple regression analysis showed a significant correlation between body fat mass and duration of breast-feeding and lower amounts of body fat correlated with a longer period of breast-feeding.