In this study, various dental stem cells were isolated and their mineralization ability was evaluated. First, we isolated postnatal stem cells from human dental tissues such as dental pulp (DPSCs), periodontal ligament (PDLSCs), periapical follicle (PAFSCs) and mandibular bone marrow (MBMSCs). Then, we cultured these dental stem cells in the mineralization condition for 21 days. Ability of these stem cells to mineralize was evaluated by Alizarin Red staining, quantitative analysis of Alizarin Red, alkaline phosphatase (ALP) activity, and RT-PCR. The calcium deposits of PAFSCs were sparsely scattered throughout the adherent layer, whereas MBMSCs and PDLSCs cultures produced extensive sheets of calcified deposits over the entire adherent layer. Quantitative Alizarin Red staining and the ALP activity also were high in MBMSCs and PDLSCs. In the osteogenic differentiation condition, all of dental stem cells showed upregulated expression of the mineralization-related gene. Our findings suggest that isolated DPSCs, PDLSCs, PAFSCs and MBMSCs have the different mineralization abilities.