Tissue engineering has been developed recently for bone tissue reconstruction. One of the materials that has a potential to be used as a scaffold is chitosan, a natural biopolymer of chitin derivative. Currently it is not known whether chitosan can induce osteogenic differentiation of dental pulp cells. Objectives: To evaluate the potential of chitosan to induce in vitro differentiation of dental pulp cells to osteoblasts and to compare with the commonly use osteogenic supplement, dexamethasone. Methods: Research group was divided into four big group (1) dental pulp cells (DPC) cultured with various concentrations of chitosan (2.5; 5; 7.5; 10 µg/mL) (2) DPC cultured with various concentrations of dexamethosone (5, 10, 15, 20 nM) (3) DPC cultured with chitosan and dexamethasone (4) and DPC cultured with standard medium as the control group. The effect was tested on the expression of Collagen I and Osteocalcin protein by ELISA as well as ALP activity. Results: The addition of chitosan to the medium increased the protein expression of collagen I. The increase was higher compared to all concentrations in dexamethasone group. When chitosan and dexamethasone were given together in the medium no upregulation were observed compared with the chitosan group or dexamethasone group only. Conclusions: This study showed chitosan as an effective osteogenic supplement for dental pulp cells culture system corresponding to the well known osteogenic supplement dexamethasone. The results highlight the potential of chitosan polymer not only as material scaffold but also as an osteogenic signal.