Human osteoblasts isolated from bone tissue samples have their own specific antigen profile but also share expression of antigens that are characteristic of other immunocompetent cells. Given that these findings come from studies performed in primary cultures of human osteoblasts, it was decided to test whether these antigen profiles and functional characteristics are retained in a characterized osteoblast cell line (MG-63). We show that some of these characteristics are also found in the MG-63 osteosarcoma cell line. We have demonstrated, using monoclonal antibodies and cytometry, that these cells expressed CD10, CD13, CD44, and CD54 antigens but were negative for CD69 and HLA-DR antigens. Functionally, 100% of MG-63 cells showed phagocytic capacity with a high phagocytic index. This study corroborates that osteoblastic cells have an immunological profile.