Advantages and disadvantages of various methods for estimating the effect of insulin in vivo for diagnostics of insulin resistance are reviewed. Insulin resistance is the key factor for metabolic syndrome (“X syndrome”) development, the latter includes arterial hypertension, obesity, intolerance to glucose and dislipidemia. The authors emphasize that introduction of methods for insulin resistance evaluation into clinical research practice is necessary for finding out and timely correcting of metabolic disturbances, as early diagnostics of metabolic syndrome is one of the methods for primary prevention of cardio-vascular disease and diabetes 2 type.