Preventable visits to the emergency department (ED) are estimated to represent as much as 56% of overall annual ED utilization and contribute to the high cost of health care in the United States. There are more than 25 million annual pediatric ED visits. OBJECTIVE: The aim of this study was to identify factors associated with high ED utilization among children in vulnerable families. METHODS: The Fragile Families and Child Wellbeing Study is a longitudinal cohort of approximately 5000 vulnerable children. Data from the 9-year follow-up survey were used in this analysis. Bivariate and multivariate logistic regression analyses were performed to identify correlates with high ED utilization (>/=4 visits per year). RESULTS: 2631 children were included in the analysis. In a multivariate model controlling for the child's sex, race, household income, and insurance status, 4 variables were significant predictors of ED utilization: history of hospitalization within the last year (odds ratio [OR], 15.97; 95% confidence interval [CI], 6.64-38.41; P < 0.001), diagnosis of asthma (OR, 2.53; 95% CI, 1.17-5.44; P = 0.02), number of child's office/clinic visits within the last year (OR, 1.22; 95% CI, 1.12-1.33; P < 0.001), and number of primary caregiver ED visits within last year (OR, 1.15; 95% CI, 1.03-1.28; P = 0.01). CONCLUSIONS: History of hospitalization, outpatient visits, primary caregiver ED utilization, and diagnosis of asthma independently predict high ED utilization by 9-year-old children in fragile families. Augmented continuity of care, disease management, and caregiver education may reduce high ED utilization in this population.