Mesenchymal stem cells, or (MSCs) are multipotent stem cells that can differentiate into a variety of cell types e.g osteoblasts, chondrocytes, myocytes, adipocytes, and, as described lately, beta-pancreatic islets cells (1-8) . It is accepted that these cells have the capacity to regenerate mesenchymal tissues and blood cells (1). These cells have a high potential to mislead the immune system and resistance to the functions of T , B cells and NK cells but the mechanism of action of these cells is still unclear and is believed to be due to its ability to modify the surface of the receptor cells (1) (2). Bone marrow is the main source and the Statute of the mesenchymal stem cells and the Center for Clinical Research and Altjeribh scientists were able to isolate these cells and study ( 9 ) . These cells have the ability to differentiate in vitro under specific circumstances to adipocyte, osteoblast, and chondrocyte cells (11 ) .However, there are some problems for the bone marrow derived mesenchymal stem cells involves the difficulty of access, few number and lack of differentiation as they age ( 1 ) . As a result, scientists have tended to find other sources to isolate mesenchymal stem cells and the progress of these studies it was possible to isolate these cells from adult tissues ( adipose tisse, and peripheral blood ) and embryonic tissues ( particular parts of the placenta , and umbilical cord ) (1-7). The placenta and umbilical cord is a rich source of stem cells and is known as the placenta is the fetal Umayyad formed by the embryonic tissue and the mother and the umbilical cord is the means of communication between them and this clear their importance in the process of embryonic development ( 3) . In the past, and until recently he disposed of the placenta and umbilical cord as medical waste, but the progress of research and studies Been considered as an important source for stem cell research and isolated in a safe (3) . placenta Containing the stem cells and intermediate, which is believed to be embryonic retains some characteristics (7) . were superior to cells Mesenchymal stem tissue from adult (3) (10) , It also the umbilical cord contains hematopoietic stem cells and mesenchymal stem cells, which can be isolated from umbilical cord blood and Wharton’s jelly , The cord blood is an important source for Stem cell research and use in agriculture for several reasons (5).(3)• It contains a higher number of primitive hematopoietic stem cells (HSC) per volume unit, which proliferate more rapidly than bone marrow HSC (1) .• collection of these tissues posesfewer ethical issues since these tissues are usually discarded as biological waste (12) .• Transplantation does not require a perfect HLA antigen match (unlike in the case of bone marrow) (1) .• The UC blood has already been successfully used in the treatment of inborn metabolic errors (1) . • There is a lower risk of rejection after transplantation (1) (10)• the tissues are available world-wide,and thus it would promote MSC-based research all across the globe (12). Thus, mesenchymal stem cells has become of interest to scientists and researchers have focused on their ability to differentiate and its uses in the field of regenerative medicine ( 1-11 ) . Accordingly, the main objectives of the present thesis were designed .