OBJECTIVE: To evaluate the influence of lipid and glucose metabolism in the metabolic syndrome on aortic pulse wave velocity (PWV) and left ventricular (LV) diastolic function using magnetic resonance imaging (MRI). RESEARCH DESIGN AND METHODS: Aortic PWV and LV diastolic function were assessed using MRI in 16 subjects with the metabolic syndrome and 16 subjects without the metabolic syndrome matched for age, waist circumference, and blood pressure. The groups were compared using the unpaired t test or Mann-Whitney U test, and linear regression analysis was applied. RESULTS: Aortic PWV was increased and LV diastolic function was decreased in subjects with compared with those without the metabolic syndrome. HDL cholesterol was independently associated with aortic PWV (R = -0.470, P < 0.01) and LV diastolic function (R = -0.421, P = 0.02). CONCLUSIONS: Increased aortic PWV and decreased LV diastolic function is observed in subjects with the metabolic syndrome, regardless of blood pressure. Moreover, HDL cholesterol is independently associated with aortic PWV and LV diastolic function.