BACKGROUND: The clinical value of the diagnosis of metabolic syndrome (MS) in children and adolescents remains unclear. The aim of the present study was to assess the occurrence of metabolic complications, other than included in 2007 IDF MS definition, in obese children and adolescents METHODS: The study included 75 (33 boys) obese adolescents (mean age 13.9 years, mean BMI SDS 4.49). Classical (fasting glucose, TGL, HDL, blood pressure) and non classical (insulin resistance [HOMA-IR], creatinine, AST, ALT, uric acid, fibrinogen, liver US and 24h BP profile) risk factors were compared between groups with and without MS. 15(8 boys) met the 2007 IDF criteria for MS. RESULTS: Patients with MS presented with significantly lower: BMI SDS (4.2 vs. 5.8, p=0.02), mean 24h SBP (0.8 vs. 1.0, p=0.03), and uric acid level (352.1 vs. 414.0, p=0.01). In both groups a significant percentage of abnormal results of 24hABPM (up to 42.9 and 57.6%), insulin resistance (85.7 % and 61.1%), non alcoholic fatty liver disease (57.4 % and 38.9 %) and hyperuricemia (69.2 % and 55.3%) was observed. CONCLUSION: Recognizing the metabolic syndrome in adolescents does not provide any additional clinical benefits. It seems that in every obese child a wide, personalized diagnostic work-up should be performed.