Background: Stem cells are one of the most recent and effective regenerative therapeutic techniques for various tissues damages. Aim: The purpose of this study was to study the effect of bone marrow derived stem cells injection on age changes of submandibular salivary glands Methods: Fifteen male albino rats (aging six months and weighing 100-150 grams each) served as group I, were administered saline. Thirty old male albino rats (aging fifteen months and weighing 200-250 grams each) They were fed the standered laboratory diet and divided equally into group II were get infused with saline intravenously and group III were subjected to intravenous infusion by mesenchymal stem cells. Rats were sacrificed after 4 weeks. The submandibular salivary glands were dissected out and prepared for histological and immunohistochemical examinations.. Results: Light microscopic examination of old aged group II, revealed generalized atrophy of the secretory portions with numerous intracellular vacuoles. Secretory cells revealed deeply stained pyknotic nuclei. The granular convoluted tubules showed generalized atrophy with complete loss of their eosinophilic granules. The excretory ducts appeared dilated with degenerated epithelial lining and retained secretion. Widening of the connective tissue septa with chronic inflammatory cells infiltration was also detected. While BM-MSCs treated group III, revealed well defined serous acini having distinct outline. Well formed striated ducts were also detected. Immunohistochemical examination of cytokeratin # 5, 6 & 18 and myosin expression among the studied groups revealed that their immunoreactivity was significantly reduced in the old age rats (Group II) than those of both groups I & III. Also, statistical analysis of bax expression revealed that their immunoreactivity was significantly increased in the old age rats (Group II) than those of both groups I & III. Conclusion: Intravenously administration of BM-MSCs played a tangible role in ameliorating age related changes in submandibular salivary glands.