This study was designed to investigate the anti-diabetic effects of selenium nanoparticles (SeNPs) at dose 2 mg/kg body weight in streptozotocin (STZ) induced diabetes in rats at dose 50 mg/kg body weight. Were administered orally in normal and experimentally induced diabetic rats for 35 days and glibenclamide (Glib) at the dose rate of 20 mg/kg was used as a reference drug. 48 waster male rats divided into 6 equal groups each of 8 rats. Blood samples and pancreatic tissue were collected at the end of experimental. Animals either treated with SeNPs its results demonstrated that SeNPs could significantly decreased blood glucose levels, enhanced serum insulin concentration, Result showed decrease liver function as in alanine aminotransferase (ALT) and aspartate aminotransferase (AST), decrease cardiac function creatine kinase-MB (CK-MB). total cholesterol, triglyceride and low density lipoprotein (LDL) levels significantly decreased and high density lipoprotein (HDL) significantly increased. Histological study finds that SeNPs were able to prevent pancreatic tissue atrophy in island of Langerhans cells compared to uncontrolled group < /p>