['The objective was to investigate the prevalence of metabolic syndrome (MetS), its cardiovascular disease (CVD) risk and its association with peripheral arterial disease, defined by a low ankle-brachial index (ABI) (< 0.90), in primary prevention.', 'Cross-sectional study performed in the primary care general population, aged 50-79 years. CVD risk and ABI were measured in persons without known arterial disease with MetS and in a control group. MetS was defined by Adult Treatment Panel III. CVD risk was estimated using the Systematic Coronary Risk Evaluation (SCORE).', 'A total of 581 subjects were recruited. The prevalence of the metabolic syndrome was 30.8% (95% confidence interval [CI], 27.0-34.5). For the CVD risk and ABI studies 217 individuals were included (138 with MetS and 49 with diabetes). Average CVD risk was high (5%) on patients with MetS and twice as much as those without MetS. ABI was low (< 0.90) on 15 subjects [6.9% (95% CI), 3.5-10.2], with higher frequency in the MetS group: 14 patients (10.1%) vs 1 patient (1.3%). The frequency of low ABI in patients with and without diabetes was 18.3% and 3.6% respectively. Low ABI was associated to MetS, diabetes, inactivity, high risk of SCORE and less alcohol habit. In the multivariate analysis, the odds ratio for the association MetS/low ABI was 14.7 (95% CI, 1.7-123.6).'] Is [ Ankle-brachial index testing particularly indicated in patients with metabolic syndrome but without known arterial disease ]?