" The insulin resistance (IR) is a major risk factor in severe obesity. The aim of this study was to test the predictive value of presence\/absence of polymorphisms in β3-Adrenergic Receptor (ADRB3), Uncoupling Protein 1 (UCP1), Peroxisome proliferator-activated receptor γ (PPARγ) and Adiponectin (ADIPOQ) genes in diagnosing the IR in obesity.. Subjects and Methods: We studied 112 (40 M, 72 F) morbid obese (BMI: 48.5 ± 7.5 kg\/m2) subjects recruited from the outpatient obesity clinic of Federico II University Hospital in Naples. Genomic DNA was extracted from peripheral leukocytes with a commercial kit. The gene polymorphisms Trp64Arg in ADRB3, -3826 A>G in UCP1, Pro12Ala in PPARγ and c.268G>A, c.331T>C and c.334C>T in ADIPOQ were characterized by TaqMan assay or by direct sequencing (ADIPOQ).. Results and conclusion: Our results demonstrate that -3826A>G UCP1 polymorphism is associated with IR in morbid obesity. Further, the lack of any polimorphisms: Trp64Arg in ADRB3 and\/or -3826 A>G in UCP1 and\/or Pro12Ala in PPARγ and\/or c.268G>A, c.331T>C and c.334C>T in ADIPOQ, appears an useful prognostic factor (NPV=100%) toward the IR insurgence in these obese patients.. . "