Introduction: Obesity in children and adolescents is a public health problem that is increasing worldwide, being known its relation with the development of metabolic alterations like diabetes mellitus type 2. Objectives: To determine the presence of insulin resistance in obese and non obese adolescents according to sex, age, pubertal stage and presence of familial metabolic or cardiovascular disorders. Design: Cross-sectional observational and analytical study. Setting: Three Lima urban educational centers. Participants: Adolescents 10 to 17 year-old. Interventions: Sixty nine adolescents between 10 and 17 years old were divided in two groups according to the presence of obesity. Obesity was defined as body mass index >95th percentile, 55,1% were male and 44,9% female. Homeostatic model assessment was employed to determine insulin resistance (HOMA-IR) and beta cell function (HOMA%B) i...