Breast feeding and mother-newborn attachment during the first 6 months of life are responsible in the future physical, emotional and intellectual health of newborns and their mothers. Since the ancient work of Harlow, evaluating the maternal behaviour in mammals, to recent studies and reports from nutritional experts of the Paediatrics American Academy allow us a better understanding of the physiology and the importance of breast feeding and mother-newborn attachment in human development, besides the great challenge that health professionals have in its promotion and prevention of pathologic mother-newborn attachment