Introduction: Lifestyle modification is one of the methods to promote healthy lifestyle among adolescents. In this study, the researcher planned to develop, implement and evaluate a need based Participatory Adolescent Strategic Health Action (PASHA) for lifestyle modification among selected adolescents. Materials and Methods: An evaluative approach with Quasi experimental one group pretest post test design (time series) was adopted. Sample constituted 103 adolescents, aged 12-17 years studying in high schools and pre university colleges of Udupi district selected based on convenient sampling. Data was gathered using reliable and valid tools. Results: The mean combined preventive health lifestyle score among all adolescents increased from 75.65-81.56. Similarly the number of adolescents with healthy lifestyle score also increased from 28.2-53.4% after practicing for 180 days. Analysis of all the components of lifestyle showed that the adolescents had adopted healthy lifestyle practices in all the components of lifestyle. The number of adolescents with combined health status score also showed an increase from 31.1-54.4% after implementing PASHA practice. Analysis of reported outcome among subjects indicated that PASHA was motivating to improve their lifestyle practices. Conclusion: PASHA was found to be effective in lifestyle modification of adolescents. It is reiterated that when lifestyle modification is to be done, a strategy to improve self directedness and self efficacy should be adopted.