Hyperinsulinemic euglycemic clamp is known to be the "gold standard" in measurement insulin sensitivity. However, its time and financially consuming realization led to a simplified approach in quantification of insulin sensitivity. Various indices of insulin sensitivity/resistance using the data from an oral glucose tolerance test were proposed in last 20 years. The aim of this review is to evaluate critically the use of some of the proposed indices in insulin sensitivity estimation. There are two groups of insulin sensitivity indices: 1. indices calculated by using fasting plasma concentrations of insulin, glucose and triglycerides, 2. indices calculated by using plasma concentrations of insulin and glucose obtained during 120 min of a standard (75 g glucose) oral glucose tolerance test. Some authors used demographic parameters (BMI, age, weight) in their formulas to achieve the best correlation with euglycemic clamp data. These indices are conveniently used in epidemiological and clinical studies to predict diabetes development in a non-diabetic population. Their use in clinical practice is limited because of the absence of reference values for normal and impaired insulin sensitivity.