Introduction: Obesity is becoming an increasingly prevalent problem in both developing and developed world. Childhood obesity is a serious medical condition that affects children and adolescents. It occurs when a child is well above the normal weight for his/her age and height. The important obesity risk factors in which different studies revealed genetic history, lack of physical activity, high birth weight, and type of milk of consumed during infancy, more than two hours television watching per day, number of regular meals and parental overweight as the risk factors of obesity. Oobjectives: To evaluate the effectiveness of educational programme on knowledge regarding childhood obesity among school children. To associate the level of knowledge on obesity with selected demographic variables. Methods and materials: Quantitative research approach was used to find out the knowledge on childhood obesity among school children. The research design was adapted for the study was Pre…experimental one group pre test and post test design with the objective of evaluate the effectiveness of educational programme on knowledge regarding childhood obesity among 148 school children 8th and 9th standard in Dr.Ambethkar government higher secondary school, Kirumampakkam village, Puducherry. Non-Probability convenient sampling technique was used to select the samples. Structured questionnaire were used to assess the knowledge of school children regarding childhood obesity. Major findings: The overall analysis of level of Pre test knowledge of children regarding childhood obesity shows that, out of 148 samples111 (75%) children had inadequate knowledge, 35(23.6%) children had moderate adequate knowledge and 2(1.4%) children had adequate knowledge. After the educational programme, the post test knowledge of 148 samples were, 84(56.8%) children had moderate knowledge and 64(43.2%) children had adequate knowledge. There was no significant association between the demographic variables and knowledge level of the children. Conclusion: The results shown that, the educational programme of obesity was improved the knowledge regarding obesity among the school children.