Recently many researchers have described the presence of insulin resistance and hyperinsulinemia in a substantial number of patients with essential hypertension. Reduced insulin binding to the receptors may play important role in development of insulin resistance in these patients. The study was aimed to assess the value of insulin binding to erythrocyte receptors in the patients with essential hypertension and compare to values in healthy persons. Additional purpose was the evaluation of insulin degradation by erythrocytes in patients with essential hypertension. 23 patients with essential hypertension (BMI 22.7 +/- 3.2) and 21 healthy persons (with BMI value 23.3 +/- 2.9) were studied. In all examined individuals the blood glucose and blood insulin concentrations were determined, insulin binding to erythrocyte receptors and insulin degradation by erythrocytes were measured by the method of Gambhir and al. Insulin concentration was significantly higher in patients with essential hypertension than in healthy subjects. We demonstrated a statistically significant positive correlation between body weight and insulin concentration in blood serum only in healthy people. Insulin binding to the receptors of red blood cells was significantly stronger (p < 0.001) in healthy persons than in patients with essential hypertension (0.972 +/- 0.395 pg 10(11) RBC and 0.446 +/- 0.14 pg 10(11) RBC respectively). In patients with hypertension insulin binding to receptors of red blood cells does not depend on body weight and insulin concentration in blood serum. Values of insulin degradation by erythrocyte in patients with essential hypertension and healthy persons were not significantly different. It seems that decreased insulin binding to insulin receptors is an important mechanism of insulin resistance patients with essential hypertension.