The management of breast cancer during pregnancy is one of the great clinical challenges in oncology. Patients are best served by care provided through a multidisciplinary team including surgeons, oncologists, obstetricians and genetics counsellors with experience in caring for similar women. The risks of diagnostic and therapeutic interventions can be mitigated by the consideration of known side effects of therapy on the fetus and the mother. However, because of the limited amount of clinical experience available, the potential risks to the patient, to the fetus and to the pregnancy are difficult to quantify. Treatment decisions need to be tailored carefully to the individual, respecting both her clinical circumstances and her personal preferences.