Introduction. The relationship between kidney dysfunction and cardiovascular system is multifaceted. Thus, the value of such a potential marker of glomerular filtration rate (GFR) as cystatin C cannot be underestimated as a predictor of the development of cardiovascular complications and atherogenesis factor in diabetes mellitus (DM) and chronic kidney disease (CKD). Objective was to evaluate the role of cystatin C as an atherogenesis factor in patients with DM and CKD. Materials and methods. The study involved 514 patients aged 25 to 80 years (the group of interest (n=449), the control group (n=65)). All patients underwent clinical and laboratory tests, sonography of the lower extremities vessels and brachiocephalic arteries (BCA). Results. The thickness of the intima-media complex increased with an increase of cystatin C level in the right carotid artery (CA) (from 0.80 [0.70; 0.90] mm to 0.97 [0.90; 1.02] mm) and in the left CA (from 0.90 [0.80; 0.94] mm to 0.92 [0.90; 1.10] mm). Logistic regression analysis demonstrated that an increase of cystatin C level > 0.93 mg/l raises the risk of intima-media thickening by 2.5 times (OR 2.505, p=0.042) and by 5 times when increase of cystatin C>1.38 mg/l (OR 4.718, p=0.001). At the same time, the association with homocysteine was unreliable (p=0.058). The level of cystatin C ≥0.82 mg/l with a sensitivity of 72 % and a specificity of 52 % allowed to predict the development of subclinical atherosclerosis in patients with DM and CKD (ROC AUC – 0.739). Conclusion. Cystatin C is not only a highly sensitive and accurate indicator of GFR, capable of detecting early stages of renal dysfunction, but also a highly effective predictive marker of atherosclerotic process in patients with DM and CKD.