Introduction Obesity is one of the most important health problems in children allover the world. The disease is detected more often nowadays and is corelated with lifestyle.

Objective The aim of the study was to detect the prevalence of obesity in teenagers, the presence of the complications of the disease and alimentation pattern.

Material and method We had studied 162 teenagers from “Gr. Antipa” collegium, Brasov. the protocol of the study consist in clinical examination, body mass index calculoation (BMI), and a questionair regarding alimentation and phisical exercises.

Results In our study cohort 102 subjects (62.96%) had BMI on the 95th percentiles for agen and sex, 18 (11.11%) on the 97th percentiles and 7 (4.3%) on the 99th percentiles. 152 (93.82%) children had had alimentation disorders(sweets, soda, chips, fast-food almost dayly and fresh fruits ocasionaly). 110 children (67.90%) had a sedentary life (TV, PC, no physical exercises). The main complications detected were hypertension (27%), hypercholesterolemia (50%), diabetes mellitus type 2 (8%)and secundary amenohreea (6%).

Conclusions Overweight and obesity is a reality in teenager cohort. More, there are present complications of the disease even in childhood. The main cause of the obesity is “life style” which include alimentation disorders and poor physical exercises. All the efforts should be made in education of the adolescents for the prevention of the obesity because an obese child shall became an obese young adult with degenerative cardiovascular pathology.