This study aimed to investigate the prevalence of depression and to identify the influencing factors of depression. Methods: The data of the 2009 Youth Health Risk Behavior web-based Survey Collected by the Korea Center Disease Control was analyzed by Chi-square test, logistic regression using the SPSS program. Results: The influencing factors of depression by general characteristics were gender, grade, school record, socioeconomic status, living with both parents and subjective health status. The influencing factors of depression by health behaviors were smoking, drinking, drug use, effort for weight loss, sleep and perceived stress. Conclusion: This study suggested that depression prevention programs should be developed in considering preventing and reducing health risk behaviors.