This study examined combat and mental health as risk factors of suicidal ideation among 2854 U.S. soldiers returning from deployment in support of Operation Iraqi Freedom. Data were collected as part of a postdeployment screening program at a large Army medical facility. Overall, 2.8% of soldiers reported suicidal ideation. Postdeployment depression symptoms were associated with suicidal thoughts, while postdeployment PTSD symptoms were associated with current desire for self harm. Postdeployment depression and PTSD symptoms mediated the association between killing in combat and suicidal thinking, while postdeployment PTSD symptoms mediated the association between killing in combat and desire for self harm. These results provide preliminary evidence that suicidal thinking and the desire for selfharm are associated with different mental health predictors, and that the impact of killing on suicidal ideation may be important to consider in the evaluation and care of our newly returning veterans.