This study evaluated the role of psychiatric morbidity in relation to a history of suicidal behavior, with a particular focus on attention-deficit/hyperactivity disorder (ADHD). Suicidality and psychiatric diagnoses were assessed in 370 incarcerated male juvenile delinquents from Northern Russia using the semi-structured K-SADS-PL psychiatric interview. A lifetime history of suicidal ideation only (24.7 %) and suicidal ideation with suicide attempts (15.7 %) was common. Binary logistic regression analysis was used to assess the role of ADHD and other psychiatric disorders in suicidal ideation and suicide attempts. A history of suicidal ideation and of suicide attempts were associated with higher rates of psychiatric morbidity and with the number of comorbid psychiatric disorders. An ADHD diagnosis was associated with an increased risk for both suicidal ideation and for suicide attempts. The comorbidity of ADHD with drug dependence further increased the risk for suicidal ideation, while ADHD and alcohol dependence comorbidity increased the risk for suicide attempts. Our findings highlight the importance of adequately detecting and treating psychiatric disorders in vulnerable youths, especially when they are comorbid with ADHD.