We investigated the relation between computed tomography measures of aortic calcification and values for bone density and the number of fragility fractures in 2348 healthy, postmenopausal women. To determine whether increases in vascular calcification and bone loss progress in parallel, baseline values were compared with measurements obtained 9 months to 8 yr later in a subgroup of 228 women. Of the 2348 subjects studied, 70% had osteoporosis, 30% had at least one vertebral fracture, and 9% had at least one hip fracture. Aortic calcifications were inversely related to bone density and directly related to fractures. After adjusting for age and potential confounders, measures for aortic calcification predicted 26.1% of the variance in bone density (P < 0.001). Compared with women without calcification, the odds ratios for vertebral and hip fractures in those with calcification were estimated to be 4.8 (95% confidence interval, 3.6-6.5) and 2.9 (95% confidence interval, 1.8-4.8), respectively. The subgroup analysis of 228 women longitudinally studied showed that the percentage of yearly increase in aortic calcification accounted for 47% of the variance in the percentage rate of bone loss (P < 0.001). Moreover, a strong graded association was observed between the progression of vascular calcification and bone loss for each quartile. Women in the highest quartile for gains in aortic calcification had four times greater yearly bone loss (5.3 vs.1.3% yearly; P < 0.001) than women of similar age in the lowest quartile. Smaller, but highly significant differences were also found between all other quartiles. We conclude that aortic calcifications are a strong predictor for low bone density and fragility fractures.