Background and Objective: Research has shown that many children in foster care later have psychosocial problems as adults; this is often attributed to cumulative adversities and a lack of supportive caregivers. The risk factors associated with foster care, such as maternal separation and multiple placements, often counteract many protective factors that can ameliorate the effects of childhood adversities. This study assessed the relationship between adverse childhood experiences (ACEs) and psychosocial well-being in women who were in foster care as children.Methods: A total of 101 women aged 18-71 years (mean, 36.83 [12.95] years) completed an anonymous online survey based on the 10-item ACE Questionnaire, the Sense of Coherence questionnaire, and the General Health Questionnaire.Results: More than 56% of respondents were identified as experiencing current psychological distress. Sense of coherence scores (mean, 54.26 [15.35]) showed a significant inverse association with both General Health Questionnaire (mean, 14.83 [5.88]) and ACE (mean, 5.68 [2.90]) scores (r = -0.64 and -0.31, respectively) and 97% reported at least 1 ACE, 70% reported ≥ 5 and 33% reported ≥ 8. Linear regressions indicated that ACEs reported to occur before foster care were associated with lower levels of sense of coherence (8%) and higher levels of psychological distress (6%). Physical neglect and living in a dysfunctional household (parental loss, maternal abuse, or household member associated with substance abuse or prison) significantly decreased during foster care by 16 and 19 percentage points, respectively. Rates of emotional and physical abuse did not change.Conclusion: The number of ACEs was associated with the level of psychological distress. Our findings suggest that children entering the foster care system are already vulnerable and at risk of experiencing ACEs during foster care and psychological distress during adulthood. Measures implemented to protect children must not cause more harm than good. Social services that preserve and strengthen the family unit and reduce the number of ACEs both before and during foster care are recommended. Social workers and clinicians who are trained to address and manage the unique developmental needs of children in foster care may help reduce the effects of ACEs and optimize developmental health.