Mesenchymal Stem Cells/Multipotent Marrow Stromal Cells (MSC) are multipotent adult stem cells present in all tissues, as part of the perivascular population. As multipotent cells, MSCs can differentiate into different tissues originating from mesoderm ranging from bone and cartilage, to cardiac muscle. Conflicting data show that MSCs could be pluripotent and able to differentiate into tissues and cells of non-mesodermic origin as neurons or epithelial cells. Moreover, MSCs exhibit non-HLA restricted immunosuppressive properties. This wide range of properties leads to increasing uses of MSC for immunomodulation or tissue repair. Based on their immunosuppressive properties MSC are used particularly in the treatment of graft versus host disease, For tissue repair, MSCs can work by different ways from cell replacement to paracrine effects through the release of cytokines and to regulation of immune/inflammatory responses. In regenerative medicine, trials are in progress or planed for healing/repair of different tissue or organs as bone, cartilage, vessels, myocardium, or epithelia. Although it has been demonstrated that ex-vivo expansion processes using fetal bovine serum, recombinant growth factors (e.g. FGF2) or platelet lysate are feasible, definitive standards to produce clinical-grade MSC are still lacking. MSCs have to be produced according GMP and regulation constraints. For answering to the numerous challenges in this fast developing field of biology and medicine, integrative networks linking together research teams, cell therapy laboratories and clinical teams are needed.