Adolescent obesity is a real public health problem due to its increasing frequency and severity. It is a chronic disease that exposes the risk of short and long term complications. This is a cross-sectional study of 32 obese children and adolescents (21 boys and 11 girls) with sex ratio of 1.9, aged 07 to 17 years followed at the outpatient endocrinology department of EPH Hassan Badi El-Harrach from March to 2018. The main metabolic complication of obesity is insulin resistance, disturbance of the lipid balance: and a state of type 2 diabetes of 6.25% and pre-diabetes 9.37%, and acanthosis nigricanse signalling glucose intolerance present in 59.375%. High blood pressure was found in 13.8% of cases. The constellation of these clinical and biological abnormalities creates the metabolic syndrome which was noted in 20.9% of cases. The short-term complications of adolescent obesity are alarming. Persistence into adulthood is real and predisposes to cardiovascular complications and incrdiovascular complications and increased morbidity and mortality.