Objective: Adolescence is a very important period of human’s life in terms of social and cultural development including emotional lability and psychosocial maturation in parallel with rapid biological changes. During this period the risky behaviors such as frequent smoking, alcohol, drugs, truancy, violence and status fault are extremly important for adolescent health and future. In this study we aimed to investigate the influencing factors, frequency and distribution of risky behaviors in adolescents aged 11 to 19 who were studying in schools in Ankara. Methods: This cross-sectional study was applied on the adoles- cents who between the ages of 11-19, a total of 2756 students in the seven types of schools in May and June of 2014 in the center of Ankara. The trends of adolescent’s risky behaviors were evaluated using İllegal Behavior Scale that was developed by Kaner. Results: Total İllegal Behavior Scale of all students in the study was determined as average point 53.95 and as median point 49. All the factors other than the type of school, on the total İllegal Behavior Scale scores were found as statistically significant effect. The most effective first three factors were determined as the status of student’s smoking, the status of drug-using friends, the average of rationing grade point (respectively; p <0.001, p <0.001, p <0.001). Male gender was more effective on the all risky behaviors other than copy and this difference between the sexes was statistically significant (p <0.001). The risky behavior which highest mean and median value was found as status crime-to behave of against rules of the school. Total İllegal Behavior Scale scores were determined as lowest scores in the students of the Arts-Fitness Schools and the Imam-Preacher Schools (p <0.001). Conclusion: As the our study, the determination of risky behaviors of adolescents and the influencing factors of risky behaviours may contribute for new methods of training and measures.