Pregnancy-associated breast cancer is defined as carcinoma diagnosed during pregnancy or breastfeeding, up to a year after delivery. Pregnant patients with breast cancer can be treated using procedures for non-pregnant patients, with some modifications designed to avoid damage to the fetus. Breastfeeding breast cancer patients need to stop immediately. Abortion before start of treatment or during therapy does not increase survival of these patients. Chemotherapy of breast cancer may start roughly from the second month of pregnancy. Effective treatment with anthracyclines, taxanes, and cisplatin is relatively safe for both mother and fetus. During pregnancy, patients can undergo surgery but are unable to undergo radiotherapy. Also, hormonal therapy and trastuzumab treatment is not safe for pregnant women with breast cancer. Prognosis of pregnant breast cancer patients is similar to non-pregnant patients. Worse prognosis was noted for breast cancer patients diagnosed during breastfeeding. After the cancer treatment is finished, breastfeeding is completely safe, but technical reasons it can usually only be done using the contra-lateral breast. Children of mothers who were treated for breast cancer during pregnancy do not show any worsening of physical and psychiatric parameters of development. Pregnancy following treatment for breast cancer does not affect the patients prognosis in a negative way, according to clinical studies, not even in patients who suffered from a hormonal-dependent carcinoma.Key words: breast cancer - pregnancy - breastfeeding - chemotherapy - radiotherapy - biological treatment - hormonal therapyThe author declares she has no potential conflicts of interest concerning drugs, products, or services used in the study.The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 10. 7. 2016Accepted: 20. 7. 2016.