Background and aims: This cross-sectional study aimed to assess the relationship between serum vitamin D levels and carotid and brachial artery distensibility in patients older than 55 years, referred to the outpatient clinic of the department of internal medicine and geriatric medicine of the Erasmus Medical Center, in Rotterdam. Methods and results: From April to July 2006 we consecutively enrolled 49 elder patients (21 men and 28 women, mean age 78 ± 8 years) without a cardiovascular event within 6 weeks before the visit. Carotid and brachial artery distensibility coefficients and serum 25(OH)D levels (mean 50 ± 28.8 nmol/L) were assessed. Multivariate analysis (with linear regression model) was performed to investigate the relation between these parameters: carotid artery distensibility coefficient was associated with serum 25(OH)D levels (β = 0.112; 95% CI 0.053 0.172; p = 0.001). Moreover, a negative association was also observed between carotid artery distensibility coefficient and mean arterial pressure (β = −0.279; 95% CI, −0.339 −0.159; p = 0.0001). On the contrary, brachial artery distensibility has shown no association with 25(OH)D levels, being negatively linked to LDL-cholesterol levels and heart rate. An association was also observed between serum 25(OH)D level and carotid artery intima–media thickness. Conclusion: Our results revealed that serum 25(OH)D levels of older men and women were associated with both structural and functional properties of the carotid artery. No association was found with the brachial artery distensibility.@en