A number of personal and sociocultural factors influence a woman’s decision to breastfeed and the duration of breastfeeding. And treated breast cancer patients have to deal with specific physical and mental-emotional changes that may affect their decision to adopt breastfeeding and their ability to breastfeed. No prospective or retrospective data have been reported, particularly comparing the prognosis of patients who breastfed after breast cancer versus those who bottle-fed their infants. The limited available evidence suggests that approximately 30% of women lactate successfully and with no detrimental effect on survival. In addition to safety considerations, the feasibility of breastfeeding is an important issue, as breast milk production is reduced in patients undergoing unilateral mastectomy or breast-conserving surgery with radiation therapy. In a series of studies of breast-conserving surgery plus radiation therapy, which used patient self-assessment, the results showed a more favorable rate of successful breastfeeding, which is consistent with historical data from previous studies of young women undergoing chest radiation therapy for Hodgkin’s lymphoma. Studies specifically on several young women with only one breast and their children have shown that there is no need to be concerned about the nutritional adequacy of the milk produced from one breast. More recently, a qualitative study of a limited sample of breast cancer patients showed that mothers were highly motivated and satisfied with breastfeeding despite the fact that the presence of almost or completely unilateral breast function made lactation difficult. Women should not be discouraged by their physicians from breastfeeding after breast cancer, but adequate counseling and practical information is needed; if breastfeeding, they should not receive any other treatment that would increase the risk of drug transmission to the baby through the breast milk.