Purpose : The purpose of this study was to examine the expression of various angiogenic factors during osteoblastic differentiation of periostealderived cells and the effects of osteogenic inductive medium of periosteal-derived cells on the proliferation of endothelial progenitor cells. Materials and methods : Periosteal-derived cells were obtained from mandibular periosteums and introduced into the cell culture. After passage 3, the cells were divided into two groups and cultured for 21 days. In one group, the cells were cultured in the DMEM supplemented with osteogenic inductive agent, including 50g/ml L-ascorbic acid 2-phosphate, 10 nM dexamethasone and 10 mM -glycerophosphate. In the other group, they were cultured in DMEM supplemented without osteogenic inductive agent. VEGF isoforms, VEGFR-1, VEGFR-2, and neuropilin-1 mRNA expression was observed. Human umbilical cord blood-derived endothelial progenitor cell proliferation was also observed. Results : The expression of VEGF isoforms was higher in osteogenic inductive medium than in non-osteogenic inductive medium. The expression of VEGFR-2 was also higher in osteogenic inductive medium than in non-osteogenic inductive medium. However, the expression of VEGFR-1 and neuropilin-1 was similar in both osteogenic inductive medium and non-osteogenic inductive medium. In addition, conditioned medium from differentiated periosteal-derived cells stimulated human umbilical cord blood-derived endothelial progenitor cell numbers compared to conditioned medium from non-differentiated periosteal-derived cells. Conclusion : These results suggest that in vitro osteoblastic differentiation of periosteal-derived cells has angiogenic capacity to support endothelial progenitor cell numbers.