The purpose of the study was to compare the clinical significance of two parameters of insulin resistance (HOMAR and ISI) in children and adolescents with obesity. Sixty-six children and adolescents aged 11-16 years, including 48 individuals with obesity and 18 healthy individuals, were examined. Anthropometric indices, the time course of changes in the concentrations of insulin and glucose during a three-hour oral glucose test, and the fasting serum concentrations of triglycerides, cholesterol, high- and low- density lipoproteins, and leptin were determined. The evaluation of the clinical significance of HOMAR and ISI consisted of three stages. A relationship between HOMAR and ISI to the most studied risk factors of insulin resistance (IR), such as obesity and the pattern of fatty tissue distribution, was studied at the first stage. Correlations of HOMAR and ISI with the anthropometric obesity indices and hormonal and metabolic parameters whose impairment is pathognomonic for IR were determined at the second stage. The spread of IR-associated disorders in children and adolescents with normal and abnormal HOMAR and ISI were compared at the third stage. The analysis has indicated that in obese children and adolescents, HOMAR is higher and ISI is lower than those in normally weighing children and adolescents of the same age, the value of ISI being inversely proportional to the excess of fatty tissue. It has been found that ISI is more closely related with the anthropometric and hormonometabolic signs of IR than HOMAR. The findings have led to the conclusion that in children and adolescents with obesity, a decrease in ISI is a more significant indicator of IR than an increase in HOMAR.