In this study, according to immunomodulatory role of mesenchymal stem cells and their role in increasing of regeneration, these cells are used to treat type-1 diabetes. Patients of both sexes in a range of 8 to 40 years old who have been diagnosed to have type-1 diabetes in no more than 6 weeks, antibody against beta cells diagnosed in their blood, fasting c-peptide more than or equal to 0.3 ng/ml, and are not suffered from other acute or chronic diseases and cancers, would be studied. In a double blinded randomized placebo-controlled phase I clinical trial, 20 patients with newly diagnosed type-1 diabetes who visited in Children’s Growth and Development Research Center of Tehran University of Medical Sciences and Royan Institute Cell Therapy Center, would be assessed through two groups including the case group (1 million autologous mesenchymal stem cells per kg of patient’s body weight in each dose, week 0 and 3) and the placebo group. Interventions: Intravascular transplantation of 1 million autologous mesenchymal stem cells per kg of patient’s body weight in each dose in week 0 and 3 in the case group & placebo injection in the control group. Outcome variables: safety of this treatment in weeks 1, 2, 3, Months 1, 2, 3, 6, 9 & 12 after first injection will be evaluated.