The cardiovascular risk of postmenopausal hormone replacement therapy is a controversial subject. A quantitative evaluation of 12 studies of cohorts show a global relative risk of major ischemic cardiac disease of 0.69 (95% confidence interval: 0.60-0.79) in women having or having had oestrogen therapy compared with women who have never taken this treatment. This relative risk was 0.94 (95% confidence interval: 0.77 to 1.15) for stroke and 0.80 (95% confidence interval: 0.65-0.97) for cardiovascular mortality. These results are coherent with the hypothesis of a protective effect of oestrogens against coronary artery disease in postmenopausal women. However, they cannot be generalised to hormone replacement therapy usually proposed in France. The influence of an association of oestrogen-progesterone therapy and the effects of administering oestrogens by an extra-gastrointestinal route on vascular risk are unknown. Randomised clinical trials are needed to determine the effects of postmenopausal hormone replacement therapy on athero-thrombotic disease.