Context: Breastfeeding has been associated with beneficial effects on the metabolic profile of women. Objective: The aim of this study was to evaluate the association between lactation and subclinical atherosclerosis in postmenopausal women. Patients: 283 postmenopausal women were recruited from the Menopause Clinic of the Aretaieio Hospital, University of Athens, Greece. Methods: The design of the study was cross-sectional. Inclusion criteria were: 1) absence of menses for at least 12 consecutive months, 2) endometrial thickness of less than 5 mm, 3) being HRT-naive, 4) without overt cardiovascular disease. Participating women underwent biochemical and hormonal evaluation. Subclinical vascular disease was defined as increased carotid and femoral intima-media thickness (IMT>0.9mm) and/or increased carotid-femoral pulse wave velocity (PWV>75th percentile, i.e. 9.5m/s) or the presence of atheromatous plaques in either carotid or femoral arteries. The absence of all was defined as healthy vascular structure and function. Results: The median number of births was 2 (0 – 4) and the median duration of lactation was 3 months (0 – 80 months). Women who breastfed for ≥3months exhibited lower odds of subclinical atherosclerosis after menopause compared to women who breastfeed for a shorter duration (OR=0.457; 95% CI: 0.254 to 0.823; p=0.009), in models adjusting for age, BMI, menopausal age, blood pressure, blood lipids and smoking. Subclinical vascular disease was prevalent in 42.7% (121/283) of women. Subclinical vascular disease was less prevalent in women who breastfed for a longer period compared to women who breastfeed for a shorter period or not at all (≥3months vs <3months: 35.7% vs 48.9%, p=0.036, Fisher’s exact test). Subclinical vascular disease was predicted by the total duration of lactation (OR=0.960; 95% CI: 0.922 to 0.999; p=0.015), age, BMI and blood pressure, in the multivariate approach. Conclusions: Women who had breastfeed their infants for at least 3 months had lower odds of subclinical vascular disease compared to women with a shorter duration of lactation. Further larger studies are necessary in order to confirm this association.