A true experimental research study to assess the effectiveness structured teaching programme on knowledge regarding prevention of obesity was undertaken. A quantitative approach with true experimental research design was used in this study. The sample size was 60, 30 in experimental group and 30 in control group. Both male and female students studying in VI, VII and VIII standard were included in the study. Simple random sampling technique was used to select the samples. The study results proved that there was significant increase in post test level of knowledge in the experimental group. No significant association was found between pretest level of knowledge in experimental and control group with selected demographic variables. Samples in the age group of 12 years with previous source of health information were found to have significant association with post test level of knowledge.