Aim: Diabetes mellitus (DM) is a chronic metabolic disease with a dramatic increase in prevalence. The current inflammatory process in diabetes mellitus leads to differentiation of the vascular endothelium and consequently microvascular and macrovascular complications. There are studies showing that ADMA and endocan measurement can be used as an endothelial dysfunction indicator. In this study, it was aimed to measure serum endocan and ADMA levels in diabetic patients and to evaluate the relationship between serum endocan and ADMA levels and microvascular complications related to hyperglycemia. Material and Methods: Eighty-five patients who were diagnosed with type 2 DM and 85 volunteers who did not have known systemic disease were admitted to study. Those with acute infection, diagnosis of malignancy, history of dialysis treatment, and any chronic inflammatory disease are not taken into account. Diabetic nephropathy, neuropathy, and retinopathy were screened in the patients. The relationship between diabetic complications and serum ADMA and endocan levels was examined. Calculated p <0.05 levels were considered statistically significant. Results: Serum ADMA levels were significantly higher in the patient group [9,42 (0,84-52,0)ng/ml]when compared to the control group[5,95(1,68-48,3)ng/ml] (p <0.001); but there was no significant difference between the patient[0,42(0,25-1,99ng/ml)] and control group[0,45(0,23-1,25)ng/ml] in terms of endocan levels (p = 0.73). Serum ADMA [respectively 9,3(0,84-52,0)ng/ml; 9,4(3,1-51,3)and endocan [respectively 0,43(0,27-1,87)ng/ml;0,41(0,25-1,99)ng/ml] levels were not significantly different in patients with microvascular complications and without microvascular complications (p = 0.884 and p = 0.355, respectively). Serum ADMA and endocan levels were not significantly different between patients who have diabetic retinopathy and neuropathy and patients who have not diabetic retinopathy or neuropathy. Serum ADMA and endocan levels were found to be significantly higher in patients diagnosed with proteinuria than in patients without proteinuria (p = 0.04 and p = 0.03, respectively). Conclusion: Our study supports the hypothesis that serum ADMA levels may be used as a marker of vascular dysfunction in DM patients with chronic low-level inflammation. However, since plasma endocan levels, which are an indicator of inflammation in the pathophysiology of disease, cannot be correlated with microvascular complications, it can be interpreted that the additional contribution of serum ADMA and endocan levels together is predictive of disease progression, limitedly.