It is generally accepted that menopause significantly modifies cardiovascular risk. The effects of hormone replacement therapy (HRT) on this risk remain controversial. Aim: To study the prevalence of cardiovascular risk factors (RF) in middle-aged women and their changes with aging, menopause and hormone replacement therapy (HRT). Material and methods: cardiovascular risk factors were assessed in 576 women aged 40 to 59 years in 1991-92. Five years later, 467 of these women were reassessed. Results: Sedentarism (87.2%), dyslipidemias (71.5%), high blood pressure (13.5%), obesity (13.1%), smoking (12.4%) and diabetes (2.8%) were the most prevalent RF. Five years later, the prevalence of hypertension increased to 20.9%, the prevalence of obesity increased to 27.3%, smoking increased to 20.8% and diabetes to 5.9%. The prevalence of dyslipidemia did not change, although triglycerides levels rose from 125.9±56.4 to 136.8±63.5 mg/dl (p <0.001). Sedentarism dropped to 58.8%. Menopause did not deteriorate any of these RF. The use of HRT increased during the 5 years follow-up from 3.8% to 35%. Women on HRT experienced 3% decrease in LDL-cholesterol and 9% increase in HDL-cholesterol levels. Conclusions: Middle aged women included in this cohort have a high prevalence of RF. There is a deterioration with age, but not with menopause. HRT improves the lipid profile (Rev Méd Chile 2003; 131: 381-9).