BACKGROUND AND PURPOSE: The metabolic syndrome (MetS) is associated with an increased risk for subsequent development of type 2 diabetes mellitus, cardiovascular disease, and stroke. Type 2 diabetes increases the risk of stroke and coronary heart disease in women to a greater extent than in men, and thus the question arises whether there are sex differences in the association of early atherosclerosis and MetS. METHODS: 1588 middle-aged Austrian subjects (1001 males, 587 females) were included in the present study. MetS was defined by the criteria of the National Cholesterol Education Program Adult Treatment Panel III. Early atherosclerosis was assessed by intima-media thickness (IMT) and extent of plaques (B-score) of the carotid arteries. RESULTS: B-score and carotid artery IMT parameters were significantly higher in subjects with the MetS. After adjustment for established risk factors, the difference in B-score remained significant only in women. Computed common carotid artery IMT values using general linear model equations with age, body mass index, and low-density lipoprotein cholesterol as covariates displayed the highest values for men with MetS (811.8+/-9.5 microm). Women with MetS (797.6+/-15 microm) and men without the syndrome (788.8+/-5 microm) showed similar IMTs, whereas women without the MetS presented significantly lower values (735.6+/-7 microm). Among the subcomponents of the MetS, high-density lipoprotein cholesterol showed the strongest impact on IMT in men, whereas blood glucose ranked first in women. CONCLUSIONS: The effect of MetS on early atherosclerosis is more pronounced in females. The impact of the components of MetS on carotid IMT differs between men and women.