Animal experiments revealed conflicting results as to the impact of bisphosphonate treatment on atherosclerosis and related vascular calcification. The effect of long-term treatment with clinical doses of bisphosphonates on aortic calcification (AC) in an "at-risk" population of osteoporotic elderly women has not been assessed systematically. In the present analysis including 474 women (55-80 years) participating in two 3-year randomized, placebo-controlled clinical trials, we assessed the simultaneous impact of ibandronate given either orally (2.5 mg daily or 20 mg intermittently) or intravenously (0.5 mg or 1.0 mg IV every 3 months) on bone mass and AC. All women received calcium and vitamin D supplements. Bone mineral density (BMD) was measured at the lumbar spine and the total hip using dual-energy X-ray absorptiometry (DXA). Calcified deposits of the lumbar aorta (L1-L4) were visualized on lateral radiographs and severity was graded by a validated scoring system. Measurements were performed at baseline and at years 1, 2, and 3. At baseline, there was a significant inverse correlation between the severity of AC and BMD at the hip (r=-0.151, P=0.003), but not at the lumbar spine. The two oral doses and the 1.0 mg IV dose evoked statistically significant increases in both hip and spine BMD compared with placebo, whereas the effect of 0.5 mg was significant only at the hip (P<0.05). No differences in the yearly rate of progression or the 3-year change in AC was observed between the different intervention groups. Furthermore, there were no statistically significant correlations between the 3-year change in BMD and the simultaneous change in AC. These findings thus suggest that 3-year treatment with effective doses of ibandronate does not pose any cardiovascular risk in terms of altering vascular calcification.