Objectives: Suicide is the major public mental health concerns all over the world. The comparison of suicide attempters and suicide completers could be the fundamental evidence for the suicide prevention. The aim of this study is to explore the differences between suicide attempters and suicide completers in terms of the stressors, suicide methods, and psychiatric diagnosis. Methods: Two types of secondary data were collected for the analyses. Data of the suicide attempters (n = 680) were gathered by intensive reviewing the medical records of Samsung Medical Center, Seoul, Republic of Korea. Data of suicide completers (n = 11,722) were collected by the psychological autopsy data which were gathered by Korean Foundation for Suicide Prevention. Suicidal methods, psychiatric disorders and stressors before suicidal attempt were compared between suicide attempter and completers. Results: Suicide completers were older and male predominant compared to suicidal attempt. Hanging or gas intoxication were more commonly used in the suicide completion, while wrist cutting or drug intoxication were more common in suicide attempters. All types of stressors were found to be high in suicide completers than suicide attempters. However, the proportion of economic and physical stress were greater in suicide completers, while the proportion of family stress were greater in suicide attempters. According to the recorded diagnoses, the rates of depressive disorders, sleep-wake disorders, substance-related disorders were higher in suicide completers, while the rates of anxiety disorders and trauma- and stressor-related disorders, bipolar and related disorders and somatic symptom disorders were higher in suicide attempters. However, after controlling the gender and age, there were no significant differences in diagnosis between suicide attempters and suicide completers. Conclusion These findings implicate that suicide attempters and completers differed in suicide methods and type of stress. The results suggests that economic stressors, physical illness might raise the risk of suicide completion.