This descriptive study was aimed at assessing the prevalence and risk factors of childhood obesity among 800 school children in Thrissur district, using simple random sampling technique. Theoretical framework of the study was based on Betty Neuman’s system model. The tools used were bio-physical measurement, body mass index (BMI) for age percentile chart for boys and girls, structured questionnaire and food frequency table. The study revealed that the prevalence of childhood obesity among school children was 5.38 percent; 9.6 percent of children had a family history of obesity; 37.6 percent children had medium risk sleep and leisure habits; 45.5 percent of the children were following medium risk dietary practices. From food frequency table (FFT), 39 percent of children belonged to medium risk group. There was significant association between family history of obesity and monthly family income with obesity among children (p<0.001) . There was no significant association between risk factors such as sleep and leisure habits, physical activity, dietary practices and frequency of food consumption per week with obesity among children. There was no significant association between socio-personal variables such as age, sex, place of residence, type of diet of child and education of parents with childhood obesity (p>0.05).