Abstract: Background and Objective: Hyperglycemia leads to changes on a cellular level that potentially accelerates to induce cell damage. This study investigated the effect of chronic hyperglycemia to superoxida dismutase and catalase activity and expression of insulin and glucagon by immunohistochemistry in rat pancreas. Methodology: Sprague dawley albino male rats (200-225 g) were divided into 2 groups. Group I was normal control, group II was hyperglycemia control. Observations were carried on the levels of blood glucose, superoxida dismutase (SOD) and catalase activities, malondialdehyde (MDA) levels, β and α-cells pancreatic immunohistochemically and histology analysis. Results: The results showed that rats experienced hyperglycemia from the 4th week and suffered hyperglycemia for 1 month with final glucose level was 139.5±5.2 mg dL–1, whereas, the glucose level of the control group was 97.8±4.3 mg dL–1. Hyperglycemia caused pathological changes in pancreatic tissue, namely increased malondialdehyde level at 31.85±5.69 pmol g–1, while MDA levels in control group only at 22.94±3.82 pmol g–1. The SOD antioxidant enzymes and catalase activities on control groups were at 31.37±3.60 and 0.85±0.08 U g–1, respectively, then they decreased to 21.18±2.34 and 0.67±0.03 U g–1 in the hyperglycemia group. Total percentages of β and α-cells in control group were 87.30±6.70 and 48.66±2.64, respectively, then they decreased to 74.54±4.35 and 41.96±2.56 in the hyperglycemia group. In hyperglycemia group, degeneration with mild degree was observed in the pancreatic cells islet of langerhans. Conclusion: Hyperglycemia lead to pathological conditions in rat’s pancreatic tissue with increased levels of malonaldehyde (MDA), decreased SOD and catalase activity, reduced expression of insulin in β-cells and nucleus of β-cell showed picnotics.