The bone marrow (BM) serves as a reservoir for different classes of stem cells. In addition to haematopoietic stem cells, bone marrow contains a population of mesenchymal stem cells (MSCs). These cells have a multilineage differentiation capacity and are able to generate progenitors with restricted developmental potential, which include fibroblasts, osteoblasts, adipocytes, and chondrocytes. Characteristic markers have been reported for expanded MSCs, but none of these markers are specific for MSCs. Thus, the objective of this study was to produce monoclonal antibodies against MSCs. MSCs derived from human bone marrow were cultured, expanded, and immunized into mice, and spleen cells subsequently harvested were used to generate hybridoma cell lines secreting antibodies against MSCs. Hybridoma culture supernatants were screened for antibodies against MSCs by enzyme-linked immunosorbent assay (ELISA), and 33 positive clones were then screened against cell suspensions of MSCs by immunofluorescence staining and flow cytometry. Ten clones were positive in immunofluorescence staining. Among these, three hybridoma cell lines, namely, YS08, YS14, and YS18 were found to be reactive with MSC by flow cytometry, but non-reactive with human tumor cell lines and hematopoietic stem cells. YS08 and YS14 showed specific bands in Western blotting. In conclusion, we developed three monoclonal antibodies, YS08, YS14, and YS18, that recognize human MSC cell surface antigen.