Background: Type 2 diabetes mellitus (T2DM) is a widespread disease. Diabetic nephropathy (DN) is one of the most prevalent and harmful effects of T2DM. Objectives: We aimed to assess blood levels of vitamin D, dickkopf1 (DKK1), hepcidin, and oxidative stress biomarkers in T2DM patients who have and do not have DN. Subjects and methods: The study comprised 55 T2DM patients, of which 35 had DN, 20 did not, and 30 were healthy controls. ELISA was utilized to estimate serum concentrations of vitamin D, DKK1, and hepcidin, while spectrophotometry was used to detect the oxidative stress indicators. Results: Comparing T2DM patients to controls and DN patients to patients without DN, serum levels of DKK1, hepcidin, lipid peroxide (LPER), and nitric oxide (NO) were considerably greater, whereas vitamin D,  glutathione peroxidase (GPx), and superoxide dismutase (SOD) were significantly lower. DKK1, hepcidin, LPER, and NO levels were considerably higher in T2DM patients with prolonged duration and inadequate glycemic control, but vitamin D, GPx, and SOD levels were significantly lower. Vitamin D, DKK1, and SOD showed the highest predictive value for T2DM. Vitamin D and hepcidin, meanwhile, demonstrated the strongest predictive value for DN. In T2DM patients, elevated hepcidin levels were strong predictor of DN. Vitamin D correlated positively with GPx and SOD and negatively with DKK1, hepcidin, LPER and NO. Conclusion: We can deduce that in T2DM patients, especially those with DN, long duration, and poor glycemic control, high levels of DKK1, hepcidin, LPER, NO, and low concentrations of vitamin D, GPx, and SOD are detected. Hepcidin may be useful in diagnosis and predicting DN in T2DM patients. This emphasizes the role of these biomarkers in pathogeneses of T2DM and DN in an effort to have potential therapeutic implications in the future.