Present study attempts to assess the knowledge and attitude regarding life style modification in prevention of obesity among adolescents with a view to develop self-instructional module in selected schools at Jaipur, Rajasthan. In this study the assessment shows the level of knowledge of adolescents regarding obesity with regard to scores, 45 (45%) Poor knowledge (1-10) and 31 (31%) adolescents regarding obesity Average knowledge (11-18) and 24 (24%) regarding obesity good knowledge (19-25) of adolescents. The level of attitude of adolescents regarding obesity with regard to scores, 45 (45%) Favorable attitude and 33 (33%) adolescents regarding obesity Neutral attitude and 22 (22%) regarding obesity Unfavorable attitude of adolescents. In this study the calculated chi square value for different age group of adolescent students were 31.09(tabulated= 0.599) which means gender create significant difference on level of knowledge score regarding prevention of obesity. The study findings reveal that the students knowledge had enhanced regarding obesity.