Introduction: Obesity and Overweight have negative health impact in adolescence, as well as in the long term, as there is an increased risk that these conditions may become chronic diseases in adulthood with numerous deleterious health outcomes and with attendant impacts on morbidity and mortality. Aim: The investigation of levels of Body Mass Index (BMI), an index of obesity, as well as factors that are related with this in students of lycee of municipality Salamine. Material and Method: The present study was prospective and took place in accidental sample of 123 students of lyceum from the 3 general lycea of municipality Salamine. In these students was shared questionnaire that concerned demographic and physical characteristics as well as their alimentary habits. For the analysis of factors which are related with the BMI we applied the multiple linear regression and for the processing and data analysis we used the statistical parcel of STATA. Results: The sample was constituted from 61 (49.6 %) boys and 62 (50.4 %) girls of age from 15.1 until 18.7 years (intermediate age 16.4 years). The medium BMI was 22.8 units for the boys and 21.6 units for the girls. From boys only 1 (1.7 %) individual was corpulent (BMI 30) though 10 (16.7 %) were overweight (BMI 25-30). In the girls there was none obese individual while 8 (13.3 %) individuals were overweight. The multivariate analysis revealed that the girls have on average lower BMI from the boys (p = 0.005) while older students had higher BMI on average from younger (p = 0.038). Also, students with change of weight in the last year (p = 0.011), attempt of diet at least once in their lives (p < 0.001) as well as those that declared bigger appetite for consumption of food (p = 0.013) had higher mean BMI. Additionally, students born in Athens had higher BMI (p = 0.020) while the frequent consumption of small quantity of food was correlated with lower mean BMI (p = 0.013). Conclusions: Obesity in adolescents is nowadays a major problem of Public Health affecting the quality of life and health of young people, but also the global economy. should A program on health education in adolescent students need to be applied, aiming to inform and change their thoughts and attitudes towards the hygiene alimentation and hygiene way of life.