This study was ordered by the Board of Directors from the Chilean Paediatrics Society and sponsored by UMCEF. It reviews the medical benefits of breast feeding and the evidence of international maternity legislation in different countries, in order to expose the principal conclusions of this analysis. Besides, it reviews the Chilean situation in terms of rules, protection and political alternatives for promoting breast feeding. An evaluation of costs and benefits is performed for breast feeding, with special attention on savings in less artificial milk consumption, less infant morbidity and decrease in nursery school attendance. With this information, many recommendations promoting the benefits of a longer postnatal license are delivered