Objective: Recently, it has been demonstrated that Mesenchymal stem cells (MSCs) which are isolated from various tissues have different potentials in differentiation and proliferation and for this reason it is necessary to isolate these cells from various kinds of origins in order to using in clinical demands. The present study has been done to investigate the possibility of isolation, culture and characterization of human synovium –derived mesenchymal stem cells. Materials and Methods: Samples (200-300 mg) were provided from synovium tissue and subsynovial inner layer of medial joint capsule of patients who had knee surgical operations. Obtained samples were homogenized, enzymatically minced with collagenase D and passed through 70 μm nylon filters and then nucleated cells were isolated and cultured. Isolated cells were identified with morphological, immunocytochemistery and differentiation tests Results: The isolated cells in this study showed fibroblast- like morphology and like the mesenchymal stem cells have high proliferation capacity. In immunocytochemical studies they were positive for CD73, CD105 and STRO-1 antigens. After induction toward osteogenic and adipogenic lineages and specific staining for each lineage it was revealed that isolated cells were potent in differentiation into mentioned lineages. Conclusion: These results suggest that synovium tissue which is discarded in most knee operations can be used for cell therapy and tissue engineering protocols as an enrichment source of potent mesenchymal stem cells.