The article considers the questions of a necessity of widening the list of obligatory preoperative examinations of patients with obesity for the choice of adequate operation volume, especially for simultaneous debulking of a greater omentum. The aim of research is an estimation of possibility of using an insulin resistance index (НОМА – IR) as a necessity criterion of simultaneous debulking of a greater omentum at operative interventions in patients with obesity.There were examined 60 persons from the surgical stationary, divided in 2 groups. 1 group included 20 patients with the normal body mass, 2 – 40 patients with different degrees of obesity. Insulin resistance was revealed on the base of glucose and insulin estimation, HOMA-IR index calculation.It was revealed, that glucose level in all patients doesn't reliably exceeds the upper threshold of norm, insulin rates don't differ from the control ones, even in patients with obesity, and rise in 20 % of patients only at 3 degree of obesity. It creates an illusion about the normal state of carbohydrate metabolism in these patients, whereas insulin resistance index estimation allows to reveal a pre-clinic stage of these disorders and to make a timely decision as to a possibility and necessity of simultaneous palliative operation as an ometnectomy that doesn't complicate a course of operation and postoperational period, but allows to decrease an expressiveness of carbohydrate metabolism disorders at obesity.The standard preoperative estimation of glucose level in blood doesn't allow to diagnose an insulin resistance state, that is patients of the high risk group of metabolic syndrome development (especially the ones with obesity) need the additional insulin estimation and insulin resistance index calculation in preoperational period.