Multiple recent works indicate that under a specific in vitro culture condition mesenchymal stem cells derived from bone marrow can be induced to differentiate into functional islet cells capable of normalizing hyperglycemia in a diabetic animal model (Zulewski et al, 2000;Chen et al, 2004; Oh et al, 2004). The present study aims to detect the differentiation of bone marrow derived mesenchymal stem cells (MSC) into functional islet beta cells and to answer which is more effective; infusion of differentiated MSC into islet cell or infusion of undifferentiated MSC and If these lines provide any improvement of some diabetic complications like cardiovascular affection in this diabetic animal model.