The abdominal aorta is known to be more susceptible to arterial dilation than to occlusion primarily due to the effects of vascular aging. Few studies have considered the effects of cardiovascular risk factors on arterial diameter, particularly within a population of healthy women at mid-life. This study seeks to examine associations between cardiovascular risk factors and abdominal aortic and iliac adventitial diameter. Abdominal aortic ultrasound was performed in 260 post-menopausal women aged 53.9+/-2.5 years at time of scan as a component of the Healthy Women Study. Risk factors were evaluated at premenopause and post-menopausal clinic visits closest in date to the abdominal ultrasound scan. Post-menopausal weight and change of weight from pre- to post-menopause were among the strongest correlates of larger adventitial diameter after controlling for age, systolic blood pressure, and body size using height. Other post-menopausal risk factors significantly correlated with both abdominal aortic and iliac diameter were BMI, waist circumference, HDL, and insulin (p<0.05). These data suggest that weight is a key risk factor in the promotion of vascular aging as indexed by enlarged arterial diameter. Women at mid-life should continue to be targeted for weight interventions to reduce their risk for more serious cardiovascular complications.