Mesenchymal Stem cells (MSCs), which contribute to the regeneration of mesenchymal tissues, were isolated from bone marrow of children with various diseases. The MSCs were purified, cultured for many passages, and allowed to proliferate extensively. The MSCs were capable of osteogenic, chondrogenic, adipogenic, myogenic, and neurogenic differentiation in culture. Comparing the MSCs from bone marrow of children with various diseases, there were no differences in their capacity to proliferate or to undergo osteogenesis, chondrogenesis, adipogcnesis, myogenesis, and neurogenesis.