Among mesenchymal stem cell (MSCs) sources, the most interesting ones in tissue engineering and regenerative medicine are oromaxillofacial tissue. Of these, dental pulp derived (DP-MSCs) MSCs are part of interest. The substantial expansion of MSCs in vitro is a requirement site to achieve adequate cell numbers for cell-based therapy. However, the limited proliferation of MSCs diminishes with long term cell culture amplification. Therefore, natural agents are being investigated to increase proliferation and/or differentiation. Lactobacillus rhamnosus draws attention with the expolysaccharides (EPSs) it produces. EPSs have been attributed to have a significant role in probiotic activity; including immunomodulatory, antitumor, cholesterol lowering, biofilm reducing, antioxidant, antiallergic, and wound healing effects. However, there is incompetent knowledge discussing their effect on DP-MSCs. In this study we aimed to demonstrate the induced proliferation, differentiation and cellular collagen secretion of DP-MSCs in response to the L. rhamnosus E9 EPSs. 1000 mu g/mL EPSs was determined as the effective concentration by using a real-time monitoring system. L. rhamnosus E9 EPS was able to accelarate ostegenic differentiation and secretion of cellular collagen. Indeed, EPS was able to decreased the calcium granules that occurs due to long term cultivation. By consideration of inducing proliferation, osteogenic differentiation and secretion of cellular collagen, L. rhamnosus EPS could be considered as good candidate for preconditioning agent and/or scaffold material.