Background: In the limited research into suicides in older adults, they have been treated as a homogenous group without distinguishing between different age groups. This study aimed to compare differences in sociodemographic variables, recent life events, and mental and physical illnesses between three age groups within older adults who died by suicide: young-old (65-74 years), middle-old (75-84 years), and oldest old (85 years and over) in Queensland, Australia, during the years 2000-2012 (N = 978). Methods: The Queensland Suicide Register was utilized for the analysis. Annual suicide rates were calculated. Odds ratios with 95% confidence intervals and χ 2 tests for trend were calculated to examine differences between the three groups. Results: Suicide rates were increasing with age for males, but not for females. Hanging and firearms were the predominant methods of suicides. However, suffocation by plastic bag and drowning as suicide methods increased with age, in contrast firearms and explosives decreased with age. Overall, psychiatric problems, suicidal behavior, legal and financial stressors, and relationship problems decreased significantly with age, meanwhile physical conditions and bereavement increased with age. Conclusion: Suicide across older adulthood is not a homogenous phenomenon. Our findings showed significant differences in the prevalence of potential risk factors within the three different age groups considered. To prevent suicide in older adults would require targeting specific factors for each subgroup while using holistic and comprehensive approaches.