Deer antler has been widely prescribed in Chinese and Korean pharmacology. Although there have been several reports concerning the effects of deer antler, such as anti-aging action, anti-inflammatory activity, anti-fungal action and regulatory activity of the level of glucose, the effect on bone has not determined yet. The purpose of this study was to examine the effect of deer antler on osteoblast differentiation. Hexane extract(CN-H) and chloroform extract(CN-C) were acquired from deer antler(Cervus nippon) and MC3T3-E1 preosteoblasts were cultured in the presence or absence of each extract. Osteoblast differentiation was estimated with the formation of mineralized nodules and the mRNA expression of alkaline phosphatase(ALP), osteocalcin(OC) and bone sialoprotein(BSP) which are markers of osteoblast differentiation. Non-treated group did not show mineralized nodule. CN-C or CN-H-treated group showed minerlaized nodules in 16 days. In northern blot analysis, CN-C or CN-H-treated group showed the elevated expression of ALP, BSP and OC in 16 days. These results suggest the possibility to develop deer antler as a bone regenerative agent in periodontal therapy by showing the stimulating activity of deer antler on differentiation of osteoblast.