Scarce data exist concerning the prevalence of irritable bowel syndrome in adolescence. Changes in lifestyle, presence of stressors and psychological vulnerability during this stage of life place adolescents in the risk group for irritable bowel syndrome. The aim of this study is to determine the prevalence of irritable bowel syndrome in adolescents who are about to begin their university studies and to identify lifestyle and psychological factors related to irritable bowel syndrome. All students newly enrolled at Abant Izzet Baysal University during the 2005-2006 academic year were recruited. Questionnaires including the Rome II questionnaire, the Beck Depression Inventory and the State-Trait Anxiety Inventory were sent to the addresses of the eligible students before matriculation to the university. A total of 2217 students completed the questionnaires, of which 2038 (91.9%) were regarded as valid. Irritable bowel syndrome prevalence was 10.8% and was significantly higher in females than in males (14.0% vs. 7.1%, p<0.001). In logistic regression analyses, gender (OR=2.48, 95% CI=1.68-3.66) and depression (OR=1.08, 95% CI=1.04-1.12) were significantly linked to irritable bowel syndrome. The prevalence of irritable bowel syndrome in this adolescent population is similar to that reported in other studies. The association of irritable bowel syndrome with depression should guide preventive and therapeutic efforts for this specific age group.