The role of lifestyle modifications, antioestrogens, cyclo-oxygenase-2 inhibitors and prophylactic mastectomy in reducing breast cancer is reviewed. It is concluded that avoiding postmenopausal obesity and regular physical activity are simple measures that seem to reduce breast cancer risk. There is no conclusive evidence that dietary modification and vitamin supplementation significantly reduce the risk of breast cancer. The evidence suggests that tamoxifen significantly reduces the risk of breast cancer in women at increased risk, but whether it reduces breast cancer mortality remains unknown. Ongoing clinical trials may prove that raloxifene is superior to tamoxifen in breast cancer prevention due to its anti-oestrogenic effects on the endometrium. Bilateral prophylactic mastectomy reduces the risk of breast cancer by 90% in high risk women.