Abstract Aim The present study aims to analyse predicting factors of suicide among older adults compared to sudden death controls and middle-aged suicides. Methods During the period 2006–2008, at two Australian sites, the psychological autopsy method was utilised to investigate suicides of individuals over the age of 35 by interviewing next-of-kin and healthcare professionals. A case–control study design was applied using sudden death cases as controls. Initial information was gathered from coroner's offices. Potential informants were approached and interviews were conducted using a semi-structured format. Results In total, 261 suicides (73 aged 60+) and 182 sudden deaths (79 aged 60+) were involved. Older adult suicides showed a significantly lower prevalence of psychiatric diagnoses (62%) when compared to middle-aged suicide cases (80%). In both age groups, subjects who died by suicide were significantly more likely to present a psychiatric diagnosis, compared to controls; however, diagnosis did not remain in the final prediction model for older adults. Hopelessness and past suicide attempts remained in the final model for both age groups. In addition, living alone was an important predictor of suicide in older adults. Conclusion Although mood disorders represent an important target for suicide prevention in old age, there should be increased attention for other risk factors including psychosocial, environmental, and general health aspects of late life.