Mesenchymal stem/stromal cells (MSCs) are heterogeneous. A fraction of these cells constitute multipotent cells that can self-renew and mainly give rise to mesodermal lineage cells such as adipocytes, osteocytes and chondrocytes. The ability of MSCs to differentiate into endothelial cells remains controversial. Isolation and in vitro manipulation of MSCs before clinical application are important steps. High numbers of MSCs are needed, requiring the in vitro expansion of these clinically important cells. To this end, a well-controlled procedure for MSC isolation and maintenance in culture is necessary.