Aim: To determine the prevalence of depressive symptoms in adolescents and explore the association of socio-demographic factors with depression. Methods: A cross-sectional study was performed in the city center of Konya, Turkey, and included all of seventh grade children in primary schools with census method. The mean age of participants was 13.6±0.7 (range 12 to 16). The data were collected with selfadministered Children’s Depression Inventory (CDI) which contains 27 items, and socio-demographic questionnaire in classrooms. Results: Of the 7602, 9.9% second part elementary school students reported depressive symptoms. There were relationships between adolescent depression and gender (OR= 2.35 for girls), age (OR= 1.67 for 15≤), low school performance (OR= 2.11), smoking of father (OR= 1.27), chronic disease of mother (OR= 1.71), chronic disease of father (OR= 1.49), family income (OR= 1.44 for poor), and father’s profession (OR= 0.69 for self-employed). Depression rate was 22.9% among the children who had lost their mother and 19.1% on the child whose parents were separated. Depression ratio was low in children whose fathers were self-employed professionals (8.4%). Conclusion: In adolescence period, especially girls and their parents should be educated about depression and the children’s school performance should be improved. The economic status of poor families and health services should be strengthened. With the help of school guiding services, the fathers who smoke should be warned.