BACKGROUND: Economic hardships imposed by the pandemic could have implications for children's experiences of adversity in the home, or Adverse Childhood Experiences (ACEs). OBJECTIVE: This observational cohort study examined associations between COVID-19-related hardships and distress (e.g., job loss, caregiver stress) and the cumulative number of child ACEs reported by caregivers during the pandemic (i.e., March 1, 2020-February 28, 2022). PARTICIPANTS AND SETTING: The study included children (N = 4345; median age = 6.0 years, interquartile range = 4-9 years) and their parents/caregivers who participated in the NIH-funded Environmental influences in Child Health Outcomes (ECHO) Program. METHODS: We described socio-demographic characteristics and pandemic-related family hardships/distress and cumulative child ACE scores reported during pre-pandemic and pandemic periods. We used negative binomial regression models to evaluate associations between pandemic-related family hardships and cumulative child ACE scores reported during the pandemic. RESULTS: Each caregiver-reported hardship/distress was associated with higher child ACE scores reported during the pandemic. After accounting for pre-pandemic child ACE scores, moderate and severe symptoms of pandemic-related traumatic stress among caregivers were associated with 108 % and 141 % higher child ACE scores reported during the pandemic, respectively, compared with no or low caregiver symptoms. In addition, finance-related stress during the pandemic was associated with 47 % higher child ACE scores. After adjusting for pre-pandemic child experiences of neglect, most sources of stress remained significantly associated with higher child ACE scores reported during the pandemic, particularly severe/very severe symptoms of pandemic-related traumatic stress among caregivers. Findings held for children with no known pre-pandemic ACEs. CONCLUSIONS: This research suggests that caregivers experiencing financial hardships and those with severe pandemic-related traumatic stress may require additional support systems during stressful events.