BACKGROUND: There is concern about the effect of the COVID-19 pandemic on psychosocial functioning among school-age children, who have faced unusual stressors during this time. Our goal was to assess mental health symptoms and social risks during COVID-19, compared to before the pandemic, for urban, racial and ethnic minority school-age children, and investigate the relationship between mental health and social risks. METHODS: We conducted a cohort study from September 2019 until January 2021 of children age 5-11 years old recruited from an urban safety net hospital-based pediatric primary care practice. We measured emotional and behavioral symptoms (including attention, internalizing, and externalizing symptoms) before and during the pandemic with the Pediatric Symptom Checklist (PSC-17). We measured social risks (including food and housing insecurity) before and during the pandemic with the THRIVE screener. We measured additional mid-pandemic COVID-related stressors with items on school participation, screens/media use, illness exposure, and caregiver mental health. We compared pre- and mid-pandemic PSC-17 symptom scores across 4 domains (total, attention, internalizing, and externalizing) and used path analysis to examine the relationship between mental health and social risks pre- and mid-pandemic. RESULTS: Caregivers of 168 children (54% non-Hispanic Black, 29% Hispanic, and 22% non-English speaking) completed the study. Children had significantly higher levels of emotional and behavioral symptoms midpandemic- vs. pre-pandemic in all domains. Significantly more children had a positive PSC-17 total score (18% vs. 8%, p < 0.01) and internalizing (depression and anxiety) score (18% vs. 5%, p < 0.001) during the pandemic vs. before, indicating clinical concerns in these areas. Caregivers reported significantly more social risks during vs. before the pandemic (p < 0.001). Mental health symptoms significantly correlated with number of social risks before the pandemic, but not during the pandemic. Less school assignment completion, increased screen time, and caregiver depression were all significantly associated with worse mid-pandemic mental health in children. CONCLUSION: The COVID-19 pandemic has led to a dramatic increase in depression/anxiety problems and social risks among urban, racial and ethnic minority school-age children compared to before the pandemic. More research is needed to understand if these changes will persist.