The aim was to assess the composition, stability and biological activity of the complexes that are formed in the solution on the interaction of calcium ions with Zolendronic acid (Zol) and study their effects on bone mineral density (BMD) indexes in female rats with experimental osteoporosis. 40 reproductive Wistar rats with systemic osteoporosis which was modeled by oophorectomy were under the study. Animals were divided into 4 groups (I -did not receive any treatment with bisphosphonates, only sufficient consumption of calcium and vitamin D (Ca-D); II -receive single dose of Zol and Ca-D; III -soluble calcium complexes of Zol (Ca-Zol) without additional use of Ca-D; IV -soluble calcium complexes of Zol with Ca-D). BMD and bone mineral content (BMC) of total body and spine were measured before treatment, after 1 and 3 months of observation by X-ray densitometer "Prodigy". Our study showed the significant positive changes in total body BMD in 1 and 3 months and spine BMD in 3 months of observation 2 d group. Analysis of BMD in rats of 3d group has not shown any significant changes of spine and total body in 1 and 3 months after its injection. However, the administration of complexes calcium and Zol with Ca-D has positive effects on total body BMDs in 1 and 3 months' follow-up and spine BMD in 3 months of observation. Analysis of BMC indices in rats of 4 th group showed the positive changes in spine and total body indexes in 1 and 3 month of follow-up, however it was not found any significant differences with animal of 2 d group. Conclusion investigated soluble complexes of calcium and Zol in combination with Ca-D supplementation showed positive effect on BMD and BMC indices, however, did not have any benefits in comparison standard administration of Zol with Ca-D supplementation.