The object of this study was to find out, what the by breast cancer affected women know about the protective effect of the breast-feeding, how long they were breast-feeding and whether they know the risk factors of the forming of this sickness. The further object was to find out which knowledge the puerperas have about the protective effect of the breast-feeding, how long they plan to breast-feed and when, from who and which information they obtain about the breast-feeding. On the basis of dialogues was found out that the women with breast cancer know very little about the protective effect of the breast-feeding. Most of them never obtained information from anybody, only some of them heard or read about the protective effect of the breast-feeding. The relationship between the breast-feeding and cancer occurrence was approved, as only one of the women breast fed for more than a year. There is a minimal knowledge of women about the risk factors. Generally, they showed three risk factors which means that the knowledge is deficient and that the education in field of precaution is necessary. In the second part of the research it was found out that the education about breast-feeding is insufficient in the maternity hospital. The hospital nurses provide information about the breast-feeding technique and the care about breasts only. The women obtained information about the protective effect of the breast-feeding at the antenatal courses, some of them from web sites or print media. The puerperas plan to breast-feed for 11.5 months on an average which shows a very positive attitude to the breast-feeding of the children.