Scintimammography is a recently verified technique that will expand the use of nuclear medicine to a new group of patients in whom scintigraphic imaging has not been widely used. If performed correctly, and in certain groups of patients, it delivers a sensitivity as high as X-ray mammography or magnetic resonance imaging (MRI) in palpable tumours but with greater specificity. It is best used in patients in whom X-ray mammography, ultrasound and MRI prove non-diagnostic or unhelpful, particularly those women with dense breasts or who have had previous breast surgery. The mechanism of uptake of 99Tcm-MIBI in breast tissue is only partly understood and in itself may help in determining important aspects of tumour function, such as the response to cytotoxic chemotherapy. Other scintigraphic methods for imaging breast cancer may be able to look at other aspects of cancer function, for example blood supply, metabolic rate or the in vivo assessment of oestrogen or somatostatin receptor status. This in turn may be useful in planning treatment. Metastatic disease may best be monitored with 18F-FDG PET, which has a sensitivity greater than MRI but a similar specificity. Much furtner work will need to be done on the use of nuclear medicine in breast cancer, but the addition of unique functional information to the anatomical data from X-ray and MRI should benefit future patients' management.