Military conflicts are ubiquitous. There are a lot of combat veterans around the world. Suicidality in combat veterans is a large and important issue. In this article, the author discusses some aspects of this issue. The combat environment is characterized by violence, physical strains, separation from loved ones, and other hardships. Combat deployment may lead to multiple emotional, cognitive, psychosomatic symptoms, suicidal ideation and behavior. Pre-deployment, deployment and post-deployment adversities may increase suicide risk in combat veterans. The act of killing in combat is a stressor which may raise suicide risk. Combat-related injuries are associated with increased suicide risk. Post-deployment difficulties of reintegrating into civilian life may lead to depression and suicidality. Studies suggest that suicidal behavior in combat veterans may have a neurobiological basis. Prevention of suicide among combat veterans should include pre-deployment screening to exclude individuals with psychiatric disorders; psychological support and prevention of harassment and/or abuse during deployment; psychosocial support after deployment; diagnosing and treating psychiatric and medical disorders including neurological disorders; frequent suicide screening; education of mental and non-mental health clinicians, war veterans, their families and friends regarding signs/symptoms of suicidality; and restriction of access to lethal means. We need to study the specific psychobiology of combat veterans to understand how to develop effective suicide prevention interventions for this population.