Obesity is defined as a body mass index more than 20 (WHO), also an individual considered to be obese when her/his body weight exceed the normal body weight. The main causes are unhealthy food, lack of physical activity, sedentary life style and genetic factors. It is an international problem, its prevalence is among both boys and girls. It is a serious problem because it has many effect on children's health. Obese child will suffer more chronic diseases like; juvenile diabetes, hypertension, heart diseases and others. Moreover obesity can lead to psychological disorders, it cause depression and it will affect children's performance at school. Obesity is incurable disease so prevention is better than cure. It could be treated by managing children's life style, changing eating habit and encourage more physical activities.