Quantification of insulin-resistance (IR) is a useful tool for evaluating its role in the physiopathology of highfrequency diseases and with high impact on the economy in public health, as well as for identifying high risk groups at its early stages The Third Adult Treatment Panel (ATP-III) has published diagnostic criteria for the Metabolic Syndrome (MS), a cluster of abnormalities related to the IR state that increases the risk of cardiovascular disease. The aim of this present study was to find the reference values of insulin, and for IR markers like HOMA and QUICKI in a healthy population constituted by a group of Public Hospital employees. Another objective was to identify subjects with IR within a sub-group carrier of MS, as defined according to the ATP-III criteria, and to correlate the IR, as evaluated by HOMA and QUICKI indexes, with the different components of the MS. We studied two groups of adult subjects from both sexes, employees at Ramon Madariaga and Province Pediatric Public Hospitals in Posadas City , Misiones Province. One group was constituted by 87 subjects with MS, and the second group by 74 subjects without MS (Control Group). Both groups represented a similar distribution of sex and age. Weight, height and waist circumference were obtained in accordance with WHO standards. Blood pressure was measured with a mercury esphybgomanometer, lipids and lipoproteins were evaluated in 12-hour fast samples, in another blood sample obtained after an 8-hour period of fasting, glycemia and insulinemia were measured. HOMA and QUICKI indexes were calculated. Internal Quality Control was performed with a serum pool prepared in the laboratory, and the External Quality Control was carried out through the controls provided by the Argentine Biochemical Foundation. Insulin was determined by radioimmunoanalysis (CV=8%) in a private laboratory at Posadas City, and for the statistical analysis of the data, Epi Info 6.04 d and SSPS 11-5 version were used. The cut off point for values found in the present study were: 12 mU/l for insulin, 2.6 for HOMA and 0.33 for QUICKI. To define IR, the 95 percentile for insulin and HOMA, and the 10 percentile for QUICKI were used, given the very strict criterion for the selection of the control group, (table 1). Sixty-six percent of the patients with MS presented IR, and no differences were observed when evaluating IR either for HOMA, or for QUICKI (figures III and IV). When correlating each of the parameters of the MS with the IR, HOMA and QUICKI indexes, significant correlations were found only with a waist (p=0.01), glycemia (p=0.01) and triglycerides (p=0.04). Due to the wide variety of cut off points used to define IR, we suggest the finding of own values of reference as those obtained in the present study. According to the surrogate markers used in this study, two thirds of the patients within the MS group presented IR, showing that not all patients with MS are IR, and therefore IR alone would not explain the presence of the MS physiopathology.