The risk of cardiovascular diseases in women is small until menopause but increases considerably afterwards. When all age groups are considered, cardiovascular diseases are responsible for approximately half of the total mortality in women. It has been suggested that hormone replacement therapy (HRT) in perimenopausal and postmenopausal women could be useful in the prevention of cardiovascular diseases, but its effects are insufficiently known. We performed a cross-sectional study on the associations of menopause and HRT with cardiovascular risk factors, in particular with hemostatic factors, on female participants of the FINRISK Hemostasis Study. The participants, aged 45 to 64 years, were recruited from the Finnish population register by random sampling from three geographically defined areas. The participation rate of women was 83.2%. Of the 1202 women included in the study, 29.2% were current users of HRT. Differences in cardiovascular risk factors by menopausal status and by HRT use were examined after adjustment for age, study area, current smoking, body mass index, self-reported diabetes, and years of education. Postmenopausal women not using exogenous sex hormones had on average a total cholesterol level 0.5 mmol/L (8.9%) higher and an LDL cholesterol level 0.4 mmol/L (11.4%) higher than premenopausal women. Women reporting irregular menstruation (presumably due to perimenopause) had higher adjusted plasma fibrinogen, factor VII coagulant activity, and factor VII antigen than women with regular menstruation or no menstrual periods.(ABSTRACT TRUNCATED AT 250 WORDS)