With an incidence of 1 case in 3 000 to 10 000 pregnancies, breast cancer is the second common pregnancy associated malignancy besides cervical cancer. An analysis of 12 patients with pregnancy associated breast cancer, treated at the University Department of OB/GYN Grosshadern, and a review of the international literature is presented. Eight women underwent surgery during pregnancy (four radical mastectomies, four breast conserving procedures), four received CMF-chemotherapy during pregnancy (1 to 4 cycles). Three other patients were treated post partum. The tumor stages were advanced (> 2 cm: 10/11; N pos.: 8/11; G3: 7/11; ER/PR neg.: 5/11). One patient with metastatic breast cancer received palliative care only and died 1 week after diagnosis and emergency caesarean section in the 31 (st) gestational week. Median overall survival was 41 months with six patients dead of breast cancer. One pregnancy was terminated in the 20 (th) week of gestation by legal abortion, another because of intrauterine death in the 24 (th) gestational week. Of the other six pregnancies, four were terminated by elective caesarean section and two by induced vaginal delivery. One child died with trisomy 18 shortly after birth. The five healthy children (now aged 3 to 12 years) showed normal development up to now. The cases show the challenge and the opportunities associated with therapy of pregnancy associated breast cancer. Utmost attention should be turned to the psychological support of the woman and her family.