This is a descriptive cross-sectional study that was carried out at Port Said city during the second term of school year 2010/2011 to estimate the prevalence of overweight/obesity among school children aged 6-12 years and to investigate the relationship between BMI (Body Mass Index) and both socioeconomic status and life style factors.After having the parents consent, eight hundred and fifty two students participated in this study. The researcher took the anthropometric measurements inside the nurse room into the school and gave the questionnaire to the students to be answered by one of child’s parents.The questionnaire was separated into two sections; first section included the anthropometric measurements, the second section included questions related to socioeconomic status, life style (physical activity and eating habits) and family history of overweight and obesity.In this study, prevalence of overweight and obesity was found to be 17.7% and 13.5% respectively among the study sample.Socio economic class, faulty dietary habits, sedentary life, low level of physical activity and positive family history of overweight and/or obesity were significantly correlated with student’s BMI.