The aim of the present study was to investigate the relationship of C-peptide levels with insulin, resistance; components of metabolic syndrome and cardiovascular disease in patients with diabetes mellitus type 2. The study included 98 patients with diabetes mellitus type 2, who were divided into two groups by the level of C-peptide. The first group consisted of 54 patients with elevated levels of C-peptide; the second group consisted of 44 patients with normal levels of C-peptide. Our study has shown a positive correlation between C-peptide levels and a body mass index (BMI), triglyceride levels and the triglyceride/high-density lipoprotein ratio. Correlation analysis also allowed identifying a statistically significant association of the HOMA-2-IR-C-peptide with a BMI, triglycerides and the triglyceride/high-density lipoprotein ratio. In the group of patients with elevated levels of C-peptide found in practically all components of metabolic syndrome, as well as a high incidence of arterial hypertension and ischemic heart disease. The study shows that the detection of the C-peptide level is preferred in comparison with insulin for assessment of insulin resistance, presence of metabolic syndrome and can be used in type 2 diabetic patients for early detection of cardiovascular risk.