PURPOSE: Risk-taking behaviors are defined as patterns of behavior initiated during adolescence which are responsible for the majority of negative health outcomes occurring during the rest of the life. The study was to explore the relationship between the risk-taking behaviors and their predisposing factors among adolescents. METHODS: The study used a survey design with an anonymous self-report questionnaire administered to 1,076 students from first year of middle school to first year of high school in Ansan City. The questions were constructed from nine risk-taking behaviors of independent variables including smoking, alcohol, drug abuse, adaptation at school, use of computer, sexual behavior, vehicle use, suicide, school violence and eight predisposing factors of school grade, gender, academic ranking, academic achievement of the mother, socioeconomic status, living with both parents, religion of the student and the mother. The data was analysed by the statistical methods of X(2) test and Fisher's exact test. RESULTS: The study revealed that the combination of the independent variables of the risk-taking behaviors to have a close association(P<0.05) with the predisposing factors. CONCLUSION: School grades, socioeconomic status, academic rankings, final educational level of the mother and living with both parents were factors strongly correlating with risky behaviors. The role of the clinician to identify those at risk is fundamental for health maintenance long after adolescence.