Up to recently women with a history of breast cancer were not allowed relief of menopausal symptoms with hormonal replacement therapy (HRT). The reasons for this attitude were the following: in vitro breast cancers are hormone-dependent tumours; the number of ovulatory cycles influences the risk of breast cancer; ovarectomy as an adjuvant measure after breast cancer is effective; anti-oestrogens are effective against breast cancer. Nowadays issues of quality of life have become more important and HRT has been reassessed in the light of the following considerations: there is no real alternative to HRT for severe menopausal symptoms; subsequent pregnancies (with concomitant high oestrogen levels) do not appear to worsen the prognosis of breast cancer; oestrogen therapy of metastatic breast cancer was described as a successful therapy in earlier times; up to now it has not been proved that HRT for a short period of time influences the risk of developing breast cancer; thus far several smaller studies of HRT after breast cancer have not demonstrated any worsening breast cancer prognosis; certain anti-oestrogens are very effective against breast cancer even though they also have a relevant tissue-specific oestrogenic activity. Furthermore, all the other positive effects of HRT (prevention of osteoporosis and lowering of the risk of myocardial infarction) are arguments for more liberal but controlled prescription of oestrogens. Until more is known about HRT after breast cancer we suggest treatment of menopausal symptoms in women with a history of breast cancer be given only within the HABITS study (HABITS: Hormonal replacement therapy after breast cancer diagnosis--is it safe?). This study has the support of the International Breast Cancer Study Group (IBCSG).