We have studied the breast-feeding frequency in Florentine Area. We investigate a group of 1364 children born between January 1985 and June 1987. We collected following data: 1) Kind of feeding at birth. 2) Duration of breast-feeding related with birth-weight, kind of delivery, mother's age, mother's working activity. 3) Growth in relation to feeding practices from birth to 3rd month. The percentage of infants breast-feed in the hospital was 81.6%, 50.5% at the end of third month, 21.9% at the end of sixth month. We have found that children weighing more than 3000 g at birth had an higher frequency of breast-feeding at birth and last longer than children weighing less than 3000 g (p less than 0.01). Maternal age had a clear effect on both the incidence and the duration of breast-feeding. Mother aged 30 years or more begin to breast-feed in lower percentage but they continue breast-feeding for a longer time. One of the factors that has a negative influence on breast-feeding at birth is caesarean section since it precludes early mother-infant contact and early initiation of breast-feeding. Mother's resume working has a negative influence on breast-feeding duration. With regard to growth in first three months of life related with different kind of feeding we have found no differences between breast-feeding and artificial-fed infants.