Many of the problems that are associated with breast-feeding appear to be caused by various postnatal care procedures that take place in the majority of our hospitals. In order to identify these obstacles, a survey was carried out on a sample of 400 mothers whose children were born in Móstoles in 1989. The results were as follows: 1) The average duration of breast-feeding was 2.43 months (SD = 2.19 months). 2) The lower the baby's birth weight and the longer that he was kept in the hospital, the shorter the time that he was breast-fed. Two basic procedures in the hospital "norms" appear to contribute to the failure of breast-feeding. First, the provision of glucose water or formula bottles and second, a ridged feeding schedule. If the newborn was fed on demand in the hospital it tended to be continued once at home. In both the hospital and in the home, on demand feeding was strongly associate with successful breast-feeding. Some simple modifications to the Maternity departments are recommended.