Objectives: This study was to examine the factors affecting Stress among adolescents in an area. Methods: Data collection was conducted by self-report survey. Survey participants were 1,255 from 11 middle and 7 high school students in a county of the Chungcheongnam-do, who were selected by the cluster sampling from May 2011. The Structural Equation Modeling was employed to investigate the research Model. Results: Tobacco errands variable was found to have a negative casual effect on self-efficacy factor and male dummy variable had a significant positive casual effect on self-efficacy. Self-efficacy had a significant negative casual effect on stress, smoke dummy variable had a statistically significant negative effect on stress and friends who smoke variable were found to have a positive casual effect on stress. Conclusions: In results, it was confirmd that the adolescents experienced more study related stress than other kinds of stress. Second, it was found out that every kind of stress are relevant to emotional problems and the behaviroral problems.