Objectives: To investigate whether high-lethality suicide attempters align to the demographic and clinical features observed in completed suicide in the national and international literature, and whether low-lethality attempters more closely align with the clinical profile of non-attempter ideators. Methods: A retrospective chart review of adult suicide ideators and attempters presenting to an urban tertiary care hospital was performed. Suicide ideators (n = 50) and attempters (n = 50) were coded for variables including demographics and clinical characteristics (e.g. psychiatric diagnosis and previous suicide attempt). Method and lethality of suicide attempt were coded using the medical Lethality Rating Scale. Results: High-lethality attempters were more likely to be younger in age than low-lethality attempters (p = 0.026) and ideators (p = 0.041). The lethality scores of suicide attempts were significantly inversely correlated with age (p = 0.017). Conclusions: Our study adds to the small but increasing body of literature investigating the characteristics of high-lethality suicide attempters and suggests younger adult age is a risk factor for a high-lethality attempt. Further understanding of this unique group would be aided by widespread agreement on the definition of a high-lethality suicide attempt and longitudinal studies of this cohort.