Insulin resistance (IR), like typeII diabetes, is being diagnosed in younger age groups. This raises the question as to which glucose and insulin values are appropriate in normal-weight, apparently healthy adults. 289female subjects aged 17-56years consented to an oral glucose tolerance test (OGTT). By definition - 90(th) percentile - the threshold values were 97mg/dl for fasting glucose, 14.8 mu U/ml for fasting insulin and 4.1 for the HOMA-insulin resistance-index (HOMA-IR). When only fasting insulin and HOMA-IR were taken into consideration, 14.9% of subjects had IR, increasing to 22.5% when insulin sensitivity based on the OGTT (Belfiore-Index) were additionally considered. These results underline the need for an OGTT with measurements of both glucose and insulin, for early detection of IR. As IR even in normal-weight, apparently healthy women can lead to serious micro-and macroangiopathy, early prevention is necessary to avoid secondary complications. So for one should discriminate between primary IR (without any pathology) and secondary IR (with additional pathology).