OBJECTIVE Research suggests that serum concentrations of 25-hydroxyvitamin D [25(OH)D] are inversely associated with hypertension incidence. This study examined whether concentrations of 25(OH)D are inversely associated with mortality risk among US adults with hypertension. METHODS We analyzed data from the 2001-2004 National Health and Nutrition Examination Survey with mortality data obtained through 2006. Hazard ratios with 95% confidence intervals (CIs) for all-cause and cardiovascular disease (CVD) mortality were estimated using Cox proportional hazard models. RESULTS Of 2609 participants with hypertension, 191 died (including 68 CVD deaths) during an average of 3.7-year follow-up. Compared with participants with 25(OH)D concentrations in the highest quartile (≥29 ng/ml), the hazard ratios for all-cause mortality were 1.93 (95% CI 1.06-3.49), 1.32 (95% CI 0.85-2.04), and 1.36 (95% CI 0.84-2.22), respectively (P for trend <0.05), and the hazard ratios for CVD mortality were 3.21 (95% CI 1.14-8.99), 2.42 (95% CI 0.85-6.90), and 2.33 (95% CI 0.88-6.12), respectively (P for trend <0.05), in the first (<17 ng/ml), second (17-<23 ng/ml) and third (23-<29 ng/ml) quartiles of 25(OH)D after adjustment for potential confounding variables. Additionally, concentrations of 25(OH)D as a continuous variable were linearly and inversely associated with the risk of mortality from all causes (P = 0.012) and from CVD (P = 0.010). These relationships were not affected much by adjustment for baseline blood pressure and use of antihypertension medications. CONCLUSIONS Concentrations of 25(OH)D were inversely associated with all-cause and CVD mortality among adults with hypertension in the US. Enhancing vitamin D intake may contribute to a lower risk for premature death.