Osteoblasts and chondrocytes are most useful cells for osteogenesis and chondrogenesis, respectively. Mesenchymal stem cells can also be used after in vitro induction or without any treatment. Meanwhile, ES cells, iPS cells and GS cells become alternative cells for osteogenesis and chondrogenesis. Cell sources for the regenerative medicine of bone and cartilage should be determined, based on "benefit" and "risk" balance in clinics.