Abstract: Background: Adverse childhood experiences (ACEs) have been associated with PTSD in military populations, but most studies assess ACEs retrospectively after trauma exposure, introducing potential recall bias. Few studies examine ACE-PTSD associations using pre-service assessments where temporal ordering is clear. Methods: This retrospective cohort study analyzed data from 288,633 Israeli Defense Forces conscripts who underwent pre-enlistment mental health evaluations between 2009 and 2019. Participants were systematically identified through universal mandatory screening, representing approximately 20 % of conscripts referred for psychiatric evaluation based on general mental health indicators. We examined associations between nine ACE types assessed before military service and combat-related PTSD diagnosed during service (ICD-10 criteria). Logistic regression models adjusted for sex, socioeconomic status, intellectual functioning, military role, and pre-service psychiatric diagnoses. Results: Combat-related PTSD was diagnosed in 165 conscripts (.06 %). In adjusted models, sexual abuse (OR = 4.14, 95 % CI: 2.34–7.33, p < .001) and emotional neglect (OR = 1.92, 95 % CI: 1.17–3.15, p = .010) were associated with PTSD risk. Physical abuse showed a borderline association in unadjusted analyses but was not significant in the final model. Conclusions: Among conscripts with elevated baseline psychiatric risk, sexual abuse and emotional neglect assessed before military service were associated with combat-related PTSD. The low case number (n = 165) limits precision of effect estimates and requires replication in larger samples. However, the study's pre-service ACE assessment eliminates recall bias, and the clear temporal ordering (ACE assessment occurred before combat exposure was possible) addresses selection concerns common in military mental health research. These findings suggest specific ACE types may warrant attention in future prospective studies examining PTSD vulnerability in military populations.