Attempted and completed suicide among older adults are increasingly significant global public health challenges. This chapter presents epidemiological data on such behaviours, addressing the risk factors in the domains of mental health, personality, physical health and functioning, social factors (e.g. life events and social support), and neurobiological mechanisms, as derived from retrospective (mainly psychological autopsy [PA] studies) and prospective case-control studies. Suicide prevention initiatives in the elderly have progressed greatly in the past decade based on better understanding of the risk and protective factors. Given the multi-determined nature of suicidal behaviours, further improvements will require sustained collaborations across clinicians, researchers, health administrators, and politicians. Furthermore, given the disparity between male and female suicide rates, research on the gender differences of suicidal behaviours is urgently needed in order to understand the different psychopathological mechanisms, and to adequately address the healthcare needs of older men, the largest group of completed suicides across the world.