Insulin resistance is the state of reduced tissue sensitivity to insulin. The frequency of this occurrence is increasing dramatically in developed countries. Both, environmental and genetic factors are involved in the pathogenesis of insulin resistance. Sedentary lifestyle and the excessive calorie intake cause the substantial increase of the fat issue, leading to overweight and obesity. Insulin resistance occurs physiologically during puberty, but it is also a pathological condition predisposing children to develop abnormal glucose tolerance, diabetes, hypertension and polycystic ovary syndrome among girls. More frequent occurrence of metabolic syndrome can be observed among children born small for gestational age (SGA). The article presents the current views on risk factors, etiology, diagnosis and consequences insulin resistance and disorders of glucose tolerance.