Childhood obesity is one of the most serious public health challenges of the 21st century. type 2 diabetes mellitus, hypertension, and hypercholesterolemia are becoming more common among obese children. This study aimed to estimate the relation between body mass index and the dietary habits, physical activity and the duration spend on electronic devices among children in Almadinah, KSA. Methodology: A community based Analytical cross-sectional study was conducted during the event of Your Health is Your Life 6th Campaign which was launched in Al Rashid Mall from 13-15/April/2017. Data were obtained based on self-filling questionnaire that included demographic, socioeconomic and lifestyle information. The body mass index was defined according to the Saudi growth charts of the ministry of health. data analysis was conducted and figured by using statistical analysis system (SAS) and Chi square tests were used to compare the result outcome variable with the studied independent factors. Results: Out of the 78 participants in the study, 70% were girls while 29.4% were boys. Based on the Saudi growth charts for BMI for age most of children in our study have normal weight (60.25%) and underweight children were (23%) while the overweight and obese group were (16.5%). According to the investigated factors in the study, consumption of fast foods and dairy products were demonstrating extreme statistically significant also the frequency of eating fruits and vegetables, regular physical activity and using of electronic devices were significant as well. Conclusion: Overweight and obesity during childhood are still remaining in increase. Dietary habits, physical activity and long duration using electronic devices are associated with increase the risk of obesity.