Local anesthetics are widely used as an intraosseous injection particularly in the field of dentistry. Occasionally, large doses of anesthetics are injected to elicit the desired effect during many surgical procedures. In this study we examined the effect of a local anesthetic, lidocaine, on osteoblasts as there are only a few reports on the effect of local anesthetics directly on bone cells. Our results showed that physiological as well as supra physiological concentrations of lidocaine cause cell death. At low concentrations, lidocaine was found to enhance both proliferation of osteoblasts and bone matrix production. In addition, low concentration of lidocaine increased the expression of osteocalcin, a key regulator in the signaling pathway of bone matrix production. Our results show that lidocaine has a biphasic effect on osteoblasts and low concentrations of this anesthetic may assist in bone matrix production. This preliminary study can lead to the therapeutic usage of intraosseous lidocaine as a bone strengthening agent.