Purpose: Against a background of a lack of systematic epidemiological research in Ireland in the area, this study set out to determine prevalence rates of psychiatric disorders, suicidal ideation and intent, and parasuicide in a population of Irish adolescents aged 12-15 years in a defined geographical area. Method: All 12-15-year olds attending eight secondary schools were eligible for inclusion. A two-stage procedure was used involving a screening and an interview phase. Those scoring in the clinical range on the screening measures were interviewed, along with a comparison group matched for gender, school and school year. Results: 19.4% of the 723 screened were identified as being ‘at risk’. This ‘at risk’ group was interviewed along with a comparison sample. 15.6% of the total study population met the criteria for a current psychiatric disorder, including 4.5% with an affective disorder, 3.7% with an anxiety disorder and 3.7% with ADHD. Significant past suicidal ideation was experienced by 1.9%, and 1.5% had a history of parasuicide. Binge drinking was associated with both affective and behaviour disorders. Conclusions: Rates of psychiatric disorders and suicidal behaviours are similar in young Irish adolescents to those in other Western cultures. Mental health promotion should be given priority in schools.