BACKGROUND Vitamin D and calcium metabolism are involved in vascular smooth muscle cell proliferation, endothelial function and blood pressure (BP) regulation. Their physiopathology has been a matter of intensive clinical investigation with variable and sometimes contradictory results. Vitamin D insufficiency is highly prevalent in the general population, particularly among the elderly. We evaluated the association between serum 25(OH)-D levels and arterial BP in this population. METHODS An epidemiological cross-sectional study was designed to analyse the prevalence of hypovitaminosis D ('D'AVIS' study) in our reference area. The study was performed on a representative random sample of the population over 64 years of age obtained from five primary health care areas. A medical record, arterial BP and biological analysis: serum 25(OH)-D, iPTH, creatinine, urea, calcium, albumin were obtained. RESULTS A total of 237 subjects (53% women), aged between 64 and 93 (mean 71.7 +/- 5.3), were evaluated. The mean serum 25(OH)-D levels were 17.21 +/- 7.57 ng/ml (interval 5-54; 86% had <25 ng/ml). The mean BP was 138.8 +/- 14/80 +/- 7.4 mmHg, and 46% were on antihypertensive treatment. A significant negative association was observed between serum 25(OH)-D levels and systolic (r = -0.153, P = 0.018) and diastolic BP (r = -0.152, P = 0.019). This association persisted after controlling for possible confounders in the multivariate analyses. CONCLUSIONS Low serum 25(OH)-D levels were inversely and independently associated with BP. Supplemental measures to prevent hypovitaminosis D in this population would be important, not only to protect the skeletal system but also for the possible beneficial effects on the cardiovascular system and the BP regulation.