Stem cells are characterized by the ability to form clones, self-regenerate and differentiate into different types of cells. Stem cells derived from human dental pulp (DPSCs) have been shown to differentiate into odontoblasts in vitro after using Bone Morphogenic Protein -2 (BMP-2). The aim of the present study was to explore the variations in the differentiation potential of the DPSC into odontoblasts in diabetic adults; it also aimed at investigating the possible influence of the origin of stem cells (coronal and radicular pulp) on their differentiation potential. Pulp tissue was extirpated from healthy individuals as well as from controlled and uncontrolled diabetic patients. Pulp tissue was divided into coronal and radicular parts and each were cultured for 30 days and then BMP-2 was added. Alizarin red staining was performed to confirm mineralization. RT-PCR was used to analyse expression of mineralization markers Dentin sialophosphoprotein (DSPP) & Enamelysin. The results of this study showed that DPSCs of both healthy and diabetic groups had stem cell properties. DPSCs of the coronal pulp have a more proliferative capacity than that of the radicular pulp. Controlled diabetes mellitus provides relatively unfavourable conditions for the DPSCs to proliferate and differentiate while uncontrolled diabetes produces more deleterious effect on the DPSCs capacity for proliferation and differentiation. Expression of DSPP and enamelysin was positive in healthy and controlled diabetics groups, while in the uncontrolled diabetic group it was negative. It is concluded that DPSCs of the coronal pulp have a more proliferative capacity than that of the radicular pulp, controlled diabetes mellitus provides relatively unfavourable conditions for the DPSCs to proliferate and differentiate and uncontrolled diabetes produces more deleterious effect on the DPSCs capacity for proliferation and differentiation.