Objective To investigate if patients with Primary Antiphospholipid Syndrome (PAPS) with venous and/or arterial thrombosis without traditional coronary artery disease (CAD) risk factors develop early atherosclerotic vascular damage. Methods 27 female patients with PAPS (Sidney criteria) and 27 age, body mass index (BMI), and sex matched controls were consecutively selected. Exclusion criteria were: black race, age 55 years, traditional cardiovascular risk factors, other thrombophilias or connective tissue diseases, corticosteroids use and pregnancy. All subjects underwent Pulse Wave Velocity (PWV) and Echo-Tracking (ET), both in carotidal bed, to analyse vascular functional properties. Results Age (p=0.92) and BMI (p=0.91) were comparable in both groups. PAPS patients and controls had similar PWV (9.071.08m/s vs 9.42 +/- 1.47m/s, p=0.34) as well as echo tracking parameters such as intima-media thickness (683 +/- 171 mu m vs 636 +/- 140 mu m, p=0.52), carotideal diameter (p=0.26), distensibility (p=0.92), compliance coefficients (p=0.36) and elastic modulus (p=0.78). Patients with exclusively venous thrombosis showed lower PWV than patients with arterial thrombosis (8.55 +/- 0.70m/s vs 9.56 +/- 0.94m/s, p=0.01), but no difference regarding intima-media thickness (683 +/- 171 mu m vs 636 +/- 140 mu m, p=0.52) was observed. Conclusion Patients with PAPS do not seem to be at higher risk of developing premature atherosclerosis. Patients who suffered exclusively venous thrombosis seem to be at lower risk than those with exclusively arterial events. Other studies need to confirm our findings.