Abstract: Previous self-harm has been identified as a risk factor for subsequent suicide by adolescents. The objective of the study was to identify further risk factors for subsequent premature death and suicide in a population of adolescents presenting with self-poisoning. A longitudinal cohort design using data-linkage of consecutive adolescent patients presenting to the Hunter Area Toxicology Service, a regional toxicology service for Newcastle, Australia, with the National Death Index of the Australian Institute of Health and Welfare was used. A total of 441 adolescents aged 10 to 19 years presented with self-poisoning over 5 years from January 1991 to December 1995, with follow-up to March 2001. There were 14 deaths total, eight of which were likely suicides. There was a 22-fold increase in suicide rate for males and a 14-fold increase for females compared with age-normalized population rates. Adjusted hazard ratios (95% CI) for premature death were male gender 3.77 (1.11-12.78), nonaffective psychotic disorders 16.3 (3.83-69.34) and the mental illnesses of childhood 6.12 (1.68-22.23). There was a similar pattern for suicide: Male gender, nonaffective psychotic disorders, and the mental illnesses of childhood confer greater risk for subsequent suicide or premature death in this population.