Abstract Background Calcific aortic valve disease (CAVD) is the most common valvular heart disease. Bisphosphonates are stable analogs of pyrophosphates and commonly prescribed in the treatment of osteoporosis. The effects of bisphosphonate treatment on CAVD are not clearly known and there are inconsistent results. Similarly, the effect of calcium supplementation on CAVD remains controversial. Purpose The aim of this study was to assess the effects of bisphosphonate therapy on the normal aortic valve and vitamin D induced in vivo rabbit aortic stenosis (AS) model. Methods The impact of calcium supplementation on the rabbit AS model was also evaluated. A total of 30 New Zealand white rabbits were divided into five equal groups: no treatment (Group I); 25,000 IU/day vitamin D3 (cholecalciferol) (Group II, rabbit AS model); 25,000 IU/day cholecalciferol plus 2500 mg/day calcium carbonate (Group III); 20 μg/kg/week intravenous alendronate (Group IV) and 25,000 IU/day cholecalciferol plus 2500 mg/day calcium carbonate plus 20μg/kg/week alendronate (Group V). Echocardiography was performed at baseline and after 12 weeks of treatment. The left ventricular mass index (LVMI), aortic valve area (AVA), transvalvular velocities and gradients were recorded. Radiologic and histopathologic examination was performed at the end of the 12th week. Control animals displayed no abnormalities of the aortic valve. Results There was no echocardiographic change in Group IV. In Groups II, III and V, there was a significant decrease in AVA and increases in transvalvular velocities and gradients. However, these stenotic changes were significantly prominent in Group V (p=0.001 for all, via repeated measures ANOVA). Moreover, LVMI was only increased in Group V (p<0.05). Calcification of aortic valvar complex was detected in 14 (46.7%) cases by radiologic imaging and 10 (33.3%) cases by histopathologic examination. Most frequent calcification was found in Group V (5 for each method, 83.3%). Agatston, volume and equivalent mass scores of calcific foci in Group V were significantly higher than other groups (p<0.05 for all). There was no significant difference between groups regarding with presence of osteoclasts in calcific foci. Conclusion Calcium supplementation has no effect on the in vivo rabbit AS model. Alendronate treatment aggravates the stenosis and increases the calcification in the rabbit AS model. Alendronate treatment has no effect on the normal valve in which there was no osteogenesis and osteoclastogenesis. Based on these findings, in patients with CAVD, alendronate treatment should be given with regular echocardiographic follow-up or may not be preferred. Central figure Funding Acknowledgement Type of funding source: None