The link between type 2 diabetes mellitus and atherosclerotic lesions in the cerebral arteries is one of the leading risk factors for acute and chronic cerebrovascular disease (CVD). Materials and methods: 126 patients with cerebrovascular disease (CVD) were examined to assess the proatherogenic blood changes: Group 1 consisted of 75 patients with CVD and type 2 diabetes mellitus (T2DM), aged 65 [55; 71] years, including 36 men; Group 2 consisted of 51 patients without T2DM, aged 66 [59; 72] years, including 23 men. The control group consisted of 32 people without CVD and T2DM, aged 63 [50; 67] years, including 17 men. All patients underwent a clinical examination, a range of biochemical blood tests, neuroimaging and vascular imaging studies. The results of the lipid panel (in particular, small dense LDL (sdLDL) and carbohydrate metabolism (glycated haemoglobin (HbA1c)) were the primary focus when the laboratory blood results were examined. Results: patients in the comorbidities group (CVD + T2DM) were more likely to have a history of CVD (52% versus 33.3% of all cases, p = 0.035) and haemodynamically significant carotid artery stenosis (38.6% versus 21.6%, p = 0.044). The concentration of hyperatherogenic sdLDL particles was also significantly higher in this group—49.1 [46.3; 53.7] mg/dL versus 33.4 [26.7; 45.6] mg/dL in patients with CVD but without T2DM, and 25.0 [19.9; 29.4] in the control group. At the same time, sdLDL values in Group 1 patients correlated with LDL, triglycerides, fasting glycaemia and HbA1c levels. Conclusion. Atherosclerotic plaques in the brachiocephalic arteries in CVD are accompanied by proatherogenic changes of the blood lipid spectrum. The sdLDL level is highest and correlates with the severity of carbohydrate metabolism disorders in patients with chronic CVD and T2DM.