The purpose of this study was to identify distinctive characteristics of old-old suicide attempters (75years and older) from young-old (60-74years old) and middle-aged suicide attempters (45-59years old). We included consecutive series of 920 patients aged 45years and older who had visited the emergency room from 2009 to 2015 because of suicide attempts. They were divided into 3 groups according to age. Information about the suicide attempt and sociodemographic status was gathered through interviews with attempters or caregivers. Chi-square test and logistic regression analysis were performed to evaluate the differences among the 3 groups. We found that old-old suicide attempters had high intent to die and high medical lethality as a result of the attempt, and illness-related problems exerted a strong motivational effect on this group. Psychiatric drugs, pesticides, and herbicides were frequently used to attempt suicide. These attempts were less likely to be associated with alcohol consumption compared to other age groups. Old-old suicide attempters have different characteristics, compared with young-old and middle-aged counterparts. It is necessary to assess suicide risk and depression when examining patients with physical illness or when prescribing psychotropic drugs. High-risk groups should be given immediate intervention including psychiatric treatment before they act on high suicide intent.