Abstract: Suicide is the second-leading cause of death for United States Military Veterans under age 45, and research suggests that adverse childhood experiences (ACEs) are a major contributor to suicide risk. The present study aimed to better understand the scope of ACEs and connections between ACEs and death ideation and suicide preparatory behaviours among U.S. Veterans who use Veterans Health Administration (VHA) services. Using VHA electronic health records data, the relationship between childhood adversity (i.e., Adverse Childhood Experiences Scale), death ideation and suicide preparatory behaviours (i.e., Columbia Suicide Severity Rating Scale) were examined. Two-stage multivariate logistic regression models evaluated the association between ACEs, death ideation and suicide preparatory behaviours, accounting for age, gender, race, ethnicity, marital status, region of residency in the U.S., and era of military service. Results suggested that standardized ACE screenings were rarely administered across VHA. 32.4% of ACEs screeners were administered at one site. ACEs were significantly related to death ideation in the past 5 years, after factoring in demographics, (OR = 1.128, 95% CI: 1.099-1.159). Similarly, ACEs were significantly related to lifetime reports of suicide preparatory behaviours (OR = 1.179, 95% CI: 1.148-1.211). Findings demonstrate the lack of ACEs screening in VHA. Despite limited screening, results suggest a significant relationship between childhood adversity and both death ideation and suicide preparatory behaviours in adulthood, suggesting individuals who report childhood adversity may be at higher risk for suicide. These findings can inform suicide screening and prevention efforts within and outside VHA.