With the presented study, it is aimed to examine the effect of dipeptidyl peptidase (DPP) 4 inhibitor sitagliptin, which is an oral antidiabetic medicine, on total antioxidant and oxidant status in the rats which were induced with the experimental type 2 diabetes (T2DM) model. The study was planned to cover 24 weeks. In rats that are left out of the control group, after 8 weeks of High-Fat Diet (HFD) feeding, the experimental T2DM model was constructed by a low double dose streptozotocin (STZ) injection per week. Sitagliptin was applied to treatment groups at a dose of 10mg/kg-day. At the end of the study, Fasting Plasma Glucose (FPG), ALT, AST, LDH, HbA1c, insulin, Total Antioxidant Status (TAS), Total Oxidant Status (TOS) levels and Oxidative Stress Index (OSI), HOMA-IR and HOMA-β indices were measured. It was determined that sitagliptin decreased FPG and HbA1c levels, increased insulin levels, and did not affect ALT, AST, LDH, TOS levels and OSI in the diabetic treatment group compared to the diabetic group. However, it was identified that sitagliptin decreased TAS levels in pancreatic tissue in diabetic rats, and decreased TOS levels and OSI in the HFD group. It was detected that in diabetic rats sitagliptin balances glucose homeostasis and protects beta cells; whereas it increases oxidative stress in pancreatic tissue and conversely it decreases oxidative stress in prediabetic obese rats (HFD groups)