Streptozocin (STZ) is a strong alkalizing agent which is capable of destroying the beta cells of the pancreatic islets. Multiple low doses (40 mg/kg, intraperitoneally for 5 consecutive days) prescription of STZ to mice can lead to the T cell-dependent immune response and induction of autoimmune diabetes (AD) with complete similarity to the human type 1 diabetes (T1D). This study has evaluated the effects of hydroalcoholic extract of saffron on the clinical and immunological profile of experimental autoimmune diabetes in C57BL/6 mice. After the establishment of the AD, mice were treated orally with hydroalcoholic extract of saffron (500 mg/kg) for 3 weeks. The results with p<0.05 were considered significant. Obtained data showed that treatment with the hydroalcoholic extract of saffron significantly reduced the incidence of hypoglycemia and restored insulin secretion and histopathological changes in pancreas sections. In addition, treatment with saffron reduced lymphocyte proliferation index in the cells isolated from the pancreas of diabetic mice. Also, the extract of saffron markedly decreased the production of pro-inflammatory interleukin-17 (IL-17) increased anti-inflammatory IL-10 and transforming growth factor-β in the pancreatic cell population. Moreover, the production of proinflammatory nitric oxide and reactive oxygen substances were down-regulated by the saffron extract. It seems that the hydroalcoholic extract of saffron can be considered as a useful strategy in the treatment of type 1 diabetes.