---

Background and Objective: Self-injury (SI), also called self-mutilation or cutting, is highly stigmatized emotional disorder. The aim of this study was to estimate the incidence rate of self-injury among male pupils in Tabriz – North West in Iran and to evaluate the associated risk factors. Materials and Methods: In this longitudinal study of all the pupils high school in Tabriz, 1772 (13.7%) were randomly sampled, and assessed in this and subsequent year. A self-administered questionnaire with 48 questions was distributed to high school in February and March 2005. After one year (February and March 2006), another questionnaire with 10-items was distributed to those students to determine the incidence rate of self-injury. The influence of different factors on self-injury was evaluated with a logistic regression model. Results: The mean age of the subjects was 16.3±0.87 (min 15, max 19) years. At the end of follow–up, 4.8% of pupils reported incidence of self-injury. Most type of incidenced self-injury were cutting and burning. The results of logistic regression model indicate that transition in smoking stages (OR=2.81), incidence of alcohol drinking (OR=2.27) and having smoker friend (OR=1.78) were factors associated with incidence of self-injury. Conclusion: This study showed that incidence rate of self-injury in this group of adolescents was 4.8% in one year, which related to age, alcohol and ciggaret smoking.