Description of Research: The pig is an ideal species for use in tissue engineering studies targeted toward repair of bone and cartilage defects. Novel collagen-glycosaminoglycan hydrogel (CG) scaffolds have shown promise for supporting bone and cartilage growth from mesenchymal stem cells. In order to determine the suitability of these scaffolds for use in porcine model systems for bone and cartilage tissue engineering, we have begun to investigate the behavior of porcine mesenchymal stem cells on this material. The purpose of this study was to determine whether mesenchymal stem cells from fat (ASC) and bone marrow (BMSC) form bone on the CG scaffold material.