Background. Osteoporosis is one of the most common yet difficult to treat diseases. It affects millions of people and costs the health care systems billions worldwide. All of the available kinds of pharmacological treatment have multiple side effects, which is why a need for safer treatment options has emerged.Objectives. This study aimed to assess the bone-healing potential of bone marrow mesenchymal stem cells (BM-MSCs) in jawbone osteoporosis in Wistar albino rats. Material and methods.Osteoporosis was induced with a daily intraperitoneal injection of 200 µg/100 g dexamethasone for 1 month. The rats were then randomly distributed into 2 groups: the osteoporotic group (left untreated); and the BM-MSCs group (received an intravenous injection of 50 million cultured BM-MSCs). Half of the rats from each group were sacrificed 2 weeks and the other half 6 weeks after the introduction of treatment. Bone regeneration was assessed by means of dual-energy X-ray absorptiometry (DEXA), real-time polymerase chain reaction (RT-PCR), as well as the histopathological and histomorphometric analyses.Results. As for the 1 st sacrifice time, there were no significant differences between the osteoporotic and BM-MSCs groups with regard to all parameters except for bone mineral density (BMD), which was significantly higher in the BM-MSCs group. Regarding the 2 nd sacrifice time, the DEXA analysis showed a significant increase in BMD in the BM-MSCs group (p < 0.001). The RT-PCR analysis showed a significant decrease in RANKL gene expression (p < 0.001) and a significant increase in OPG gene expression (p < 0.001) in the BM-MSCs group. In addition, the histopathological examination of the BM-MSCs group showed pronounced healing progress in the jawbone microarchitecture. The histomorphometric analysis also revealed that the bone area percentage significantly increased in the BM-MSCs group (p < 0.001).Conclusions. This study proved that BM-MSCs could be effective in the treatment of osteoporosis.