The aim of this study was to investigate the immunohistochemical expression of caspase-3, cyclooxygenase (COX)-1 and-2, calcium sensing receptor (CSR), and hypoxia inducible factor-1α (HIF-1α) in pancreas, liver, and kidney in streptozotocin (STZ) induced DM. The gene discussed is HIF1A; the disease is diabetes mellitus.