BACKGROUND/PURPOSE The primary purpose of this study was to examine the determinants of adolescent suicidal ideation in Taiwanese urban adolescents. METHODS A descriptive and correlational study design was used. A sample of 2341 adolescents aged from 12 to 18 years in middle and high school was recruited for this study. Data were collected between January 2005 and July 2007. Instruments used included the Children's Depression Inventory, the Cognitive Triad for Children, the Positive and Negative Suicide Ideation, the Life Event Checklist, and the revised Daily Hassle Scale. RESULTS Approximately 51% of the adolescents were identified as belonging to the high-risk group and needed further assessment for at-risk suicidal ideation. Specifically, 51.6% and 50.7% of the adolescents in middle and high schools, respectively, were identified as belonging to the high-risk groups. Results revealed that type of school, depressive symptoms, cognitive triad, and daily hassles significantly predicted adolescent suicidal ideation. Middle school students were likely to report a greater amount of suicidal ideation. Students with higher levels of depressive symptoms, negative cognitive triad and daily hassles tended to have more suicidal thoughts. The best predictor was the negative cognitive triad (beta = -0.43, p < 0.001) followed by depressive symptoms (beta = 0.35, p < 0.001). CONCLUSION Results from this study have important implications for identifying high-risk suicidal adolescent groups and for furthering suicide prevention work.