The growing incidence of the overweight has an enormous impact on increasing the risk of impaired glycemic control or insulin resistance and peripheral vascular disease. Often the problem of diagnosing errors lies in the development of contrinsular reactions in response to hyperinsulinism. The assessment of this condition is extremely complicated in the laboratory-instrumental level. Due to the rapid hormone destruction in blood serum the definition of insulin secretion is difficult. Purpose of the study: To assess correlation between microcirculation parameters and secretion of c-peptide in diabetic patients. Material and methods: A population of 72 diabetic patients was divided into 2 groups: group 1 included 31 normotensive patients with diabetes type 2 (49,7±10,9 years) with normal secretion of c-peptide (697,2±284,4 pmoll), group 2 consisted of 40 patients with diabetes (49,9±9.1 years) and c-peptide hypersecretion (1317,3±502,9 pmoll). In both groups there were the patients with the early stage of arterial hypertension. The level of glycated hemoglobin was similar in both groups: 8,37±1,9% in the 1st one and 8,2±1,7% in the 2nd one. The control group (n=43) consisted of nondiabetic normotensive individuals (50,1±9,9 years). We performed a non-invasive vital capillaroscopy (Center for Analyses of Substances) to evaluate the density of vascular network, degree of coiled capillaries, diameters of capillary parts, perivascular zone size, average capillary blood velocity (aCBV) and blood aggregation. Results: In the second diabetic group with C-peptide hypersecretion high value of BMI (Body Mass Index) was revealed, compared to the 1st group that confirmed the relationship of obesity and insulin resistance hypersecretion of c-peptide on the back of metabolic syndrome. Most important difference in microcirculation parameters was a significant expansion of the diameters of all parts of capillaries, especially of arterial one (p<0,05) that confirmed the anabolic effect of c-peptide on microcirculation system on the background of the decrease of the aCBV, which was significantly lower (p<0,03) in diabetic patients, than in the controls. Coiled capillaries quantity in both groups was significantly lower in comparison with the controls (p<0,05). There was no significant difference in the density of vascular network between the diabetic group and the controls. Conclusion: C-peptide hyper secretion resulted in microcirculation abnormalities more than diabetes with c-peptide normal secretion, especially regarding expansion of diameters of all parts of capillaries. We suppose it is possible to assess abnormal c-peptide secretion with the help of the non-invasive vital capillaroscopy. Microcirculation parameters are already changed in the first weeks of administration of drugs that affect hyperinsulinism.