The rate of suicide, which is the fourth leading cause of death in Korea, has been increasing rapidly. Thus, the development of appropriate crisis intervention and treatment approaches is important for efforts to prevent suicide. In the context of crisis intervention, interviews with persons at risk of suicidal behavior should be characterized by the following three elements: empathic communication (active listening), the evaluation of suicidal ideation and risk factors, and the enhancement of protective factors against suicide. The intensity of suicidal thoughts, thoughts of suicide methods, intent to act on suicidal thoughts, and specific suicide plans should be evaluated in detail. Risk factors associated with suicide include being male, older, or divorced; having a physical illness or a recent discharge from a psychiatric hospital; experiences of hopelessness or aggression; impulsivity; and easy access to a method of suicide. Any history of previous suicide attempts should be identified in all persons at risk for suicide because such a history is an important clinical indicator of both additional attempts and completed suicides. More than 90% of all suicides are attributable to an emotional or psychiatric illness such as depressive disorder, bipolar disorder, alcohol-use disorder, or schizophrenia. Therefore, immediate and appropriate psychiatric treatment for psychiatric illnesses related to suicide risk is essential. Hospitalization in a closed psychiatric ward can help to prevent suicide among those presenting with a high and immediate risk for suicide. In conclusion, suicide and attempted suicide can be prevented by adequate treatments such as antidepressants, lithium, clozapine, and cognitive-behavioral therapy.