BACKGROUND: The beneficial effects of the Mediterranean diet have been amply proven in adults with cardiovascular risk factors. The effects of this diet have not been extensively assessed in pediatric populations with obesity, insulin resistance (IR) and metabolic syndrome (MetS). The aim of this study was to assess the efficacy of the Mediterranean style diet (MSD) to decrease cardiovascular risk factors in children and adolescents with obesity. METHODS: Participants were randomly assigned to a MSD rich in polyunsaturated fatty acids, fiber, flavonoids and antioxidants (60% of energy from carbohydrate, 25% from fat, and 15% from protein, (n = 24); or a standard diet (55% of carbohydrate, 30% from fat and 15% from protein, (n = 25), the caloric ingest was individualized. At baseline and 16-week of intervention, the glucose, triglycerides (TG), total cholesterol (TC), HDL-C, LDL-C were measured as well as the body composition and anthropometric data. The diet compliance was determined by the 24-hour recalls.Paired Student's t and Macnemar's test were used to compare effects in biochemical, body composition, anthropometric, and dietary variables. RESULTS: The MSD group had a significantly decrease in BMI, lean mass, fat mass, glucose, TC, TG, HDL-C and LDL-C. (p < 0.05); the diet compliance increased consumption of omega 9 fatty acids, zinc, vitamin E, selenium, and decreased consumption of saturated fatty acids (p < 0.05). The standard diet group decrease in glucose levels and frequency of glucose >100 mg/dL (p < 0.05). CONCLUSION: The MSD improves the BMI, glucose and lipid profile in children and adolescents with obesity and any MetS component.