Paternal postpartum depression (the estimated prevalence in Japan is 8.8%) and anxiety (the prevalence rate ranged from 2.4% to 51.0% 1 ) are common problems. To prevent these issues, risk factors need to be identified. Besides known risk factors, 1 adverse childhood experience (ACE-) might be a significant risk factor. ACEs include all forms of physical, psychological, and sexual abuse, neglect, and household dysfunction such as parental death before the age of 18 years. Although paternal ACEs are associated with depression and anxiety during pregnancy, 2 little is known about whether the associations continue into the postpartum period. This study examines the association between paternal ACEs and paternal depression and anxiety at 1 week and 3 months post-delivery. Furthermore, we examine whether the impact of paternal ACEs on depression and anxiety varies with time.In this study, 548 fathers were recruited from two obstetrics hospitals in Tokyo, Japan. Participants gave written informed consent and completed and returned anonymous questionnaires measuring ACEs (eight questions), depression (Edinburgh Postnatal Depression Scale), and anxiety (State-Trait Anxiety Inventory) at 1 week and 3 months post-delivery. All confounders such as basic demographics were assessed at 1 week post-delivery. Four hundred and eighteen participants at 1 week (response rate = 76.1%) and 398 participants at 3 months post-delivery (follow-up rate = 93.3%) completed the questionnaire. There were no significant differences in exposure, outcome, and confounding variables at 1 week postdelivery between the participants who returned the questionnaire both at 1 week and 3 months post-delivery and those who did not return at 3 months post-delivery. Multiple linear regression analyses were performed (analytical sample: n = 417) with multiple imputations for missing data (at most, n = 37, 8.9%) (Appendix S1).Among all participants, 15.4% had one ACE, and 4.3% had two or more ACEs. As for depression, in the crude model, fathers with two or more ACEs showed a higher score of EPDS at 1 week after delivery compared to those without ACE. The coefficient remained significant in Model 2 which adjusted confounders. However, there was no significant association between paternal ACEs and depressive symptoms, 3 months after delivery, in the crude model, which was not changed in further adjustment (Model 1-3) (Table 1).