From 1978 to 1988, 611 cases of breast cancer were seen by the Mastology Department of the Beneficência Portuguesa Hospital in São Paulo, Brazil. Thirteen (2.12%) cases were associated to pregnancy, and nine (2.4%) became pregnant after treatment. The patients were submitted to surgery and the authors waited till the end of pregnancy to perform the Rt and/or Qt. Two cases could not be submitted to any kind of treatment. Whenever tests indicated fetal maturity, the option was to perform a caesarean section, and oophorectomy was performed in the most advanced cases. Among patients who became pregnant after treatment, initial cases were predominant and their pregnancies went to term with no problem. The authors compare their results to data found in literature and draw attention to anticonception in mastectomized patients.