The diagnosis of breast cancer during pregnancy is a rare event, but the young age of the patient together with the emotional impact for both the family and the doctors make therapeutic choices usually very difficult. Until recently, the occurrence of pregnancy associated breast cancer was thought to hold a grave prognosis and therapeutic abortion was very often advised in common practice. The hormonal environment with the increase in estrogens and progesterone was the main factor for the fear of tumor stimulation. The course of breast cancer, however, does not appear to be adversely affected by continuation of pregnancy. In the last years it was realized that potentially curative therapies can be administered even when pregnancy is continued. Of course in the medical literature there is no randomized clinical trial helping in taking decision in this setting; however, a significant experience already exists in some institutions and can guide management in these difficult cases. The aim of our review is to give an answer to questions usually coming from various specialists who collaborate with the oncologists in treating these patients and furthermore to try and find some basic guidelines which can be used in the information of the patients regarding previous experience in this field. The problem of a pregnancy after treatment for breast cancer is also analyzed, as this aspect is an emerging issue in clinical oncology. The decision should be evaluated for each single patient, taking into account the prognosis of the patient and her desire of pregnancy.