Understanding how to prevent suicide, the third leading cause of adolescent death, is the focus of this article. To prevent suicide, the nurse assesses risk factors, covert messages, overt suicide clues, and intervenes with the adolescent and family. Suicide risk and hopelessness decrease as suicidal youths learn to clarify problems, rally significant others, expand resources and use safe coping strategies. Interventions include a no-suicide contract, family therapy and school suicide prevention programs. Nurses can identify the youth at risk for suicide and, in many cases, provide the therapy that helps prevent suicide. Vignettes illustrate strategies that effectively reduce suicide risk.