BACKGROUND: It is evident that obesity and other associated chronic diseases are increasing. Since 1998, periodic health examination has been taken in the first grade of high school in accordance with the law nationally and will be expanded to other grades. We evaluated the health status of this population and thought the problems and pitfalls of this program. METHODS: We took 983 students of the first grade of high school in Seongnam city from April to June 2002. We used the questionnaire and test results as the first line methods of evaluation. Phone counselling was used as the follow-up method. Chi-square test was the main analytic method. RESULTS: Impaired visual acuity and absence of hepatitis B viral antibody were shown in over 40% of this population. Obesity, anemia, hyperlipidemia, hypertension were followed as the next most popular problems. Though 7.9% of 983 students were to be examined again, only 53.8% of them were re-examined. 52.7% of the student who took re-examination was proved normal. 47% of the test students thought that they were not healthy. Over half of students had the problems of exercise and eating behavior. CONCLUSION: We concluded that many students had the behavioral problems causing the chronic diseases. Medical prevention and education program is needed and medical faculties must participate in these programs. In periodic health examination various follow-up programs and screening-questionnaires on psychologic problems must be invented and applied for students.