Diabetes mellitus (DM) is characterized by hyperglycaemia that is often associated with long- term complication, including microvascular (retinopathy, nephropathy, and neuropathy) macro vascular damage. The present study was designed to evaluate the possible role of autologous bone marrow stem cell transplantation for cases of type 1 DM, which could differentiate into insulin- producing β cells and its role in modulating the immune response from T helper 1 to T helper 2. This study was conducted on 10 cases of autoimmune type 1 diabetes mellitus, both males and females. They were selected according to inclusion and exclusion criteria. We observed that 70% of studied subjects decreased in their insulin requirements. Fasting and postprandial blood glucose significantly decreased after transplantation, while levels of C- peptide were significantly increased at the end of 9 months of autologous bone marrow- derived stem cell transplantation (SCT). But glycated haemoglobin significantly decreased after transplantation. No side effects were noted in liver and kidney functions. Our observations indicated that SCT is a safe and effective modality of treatment to improve β- cell function in patients with T1DM.