Background Obesity in childhood is one of the highly risk factors for obesity in adulthood. It is one of the important causes for all the health which includes hypertension, metabolic disorders cardiovascular diseases, gallbladder disease diabetes mellitus and osteoarthritis. The prevalence of obesity and factors causing it in school going children between 5-12 years play important role to halt all diseases . Aims: Our main aim in this study is to assess the rate of prevalence of overweight and obesity among school age children (5-12 years) residing Haldia, purba Medinipur; understand the underlying various factors influencing overweight and obesity and its association with several factors affecting children’s obesity. Methodology: A cross sectional and institutional study adopting random sampling system sampling procedure. This study was done with 1200 school going adolescents of age 5 to 12 years was included in the study carried in the department of paediatrics at a medical college and hospital Age, sex, BMI, Socioeconomic status, occupation of the father, literacy status of parents, mode of conveyance to school, type and hours of physical activity, hours involved in seeing television or playing video games were assessed in the form of questionnaire. Consent has been taken from parents before proceeding study. Results: A total 1200 participants participates in this study . Among Them 60.833% were overweight and 12.5% were obese. Among them 40% were boys and 60 % were girls. Proportion of overweight was higher among girls than among boys and was statistically significant (p < 0.05). Prevalence of overweight girls peak is at age of 12 years (29.9%) compared with boys (23.58%). Obesity is significantly higher among adolescents of higher socio-economic status (16.0%) as compared to lower socio-economic group where 6.68% adolescent are obese; occupation of fathers was either service/business or the others (22.94%); children from semi private schools; and children who consume junk food (30.14%). Similarly, incidence of overweight among group – I was higher than those among group – II. It has been seen that prevalence of overweight was significantly lower among the adolescents who participated in outdoor games than those who does not participate any outdoor games (p<0.005). Discussion and Conclusions: Based on the findings of this study, it is evident that Girls are more overweight as compare of boys of same socioeconomic group. As age increases both boys and girls are obese but girls obesity rate is more as compare to boys . low levels of physical activity, watching television, and consuming junk foods are associated with a higher prevalence of overweight that can be overcome by participation in household activities, regular physical exercise, TV viewing of more than 2 hrs a day and by avoiding outside foods