Background: Growing numbers of children suffer from chronic health conditions, and initial evidence suggests chronic illness may be associated with increased child injury risk. We examined injury risk among 5-year-olds with and without chronic health conditions. Methods: Data from a diverse US sample of 7954 low-income 5-year-olds participating in the National Head Start/Public School Early Childhood Transition Demonstration Study were analysed. Mothers reported demographics, presence/absence of eight chronic health conditions, and whether children had experienced injuries requiring professional medical attention in the past year. Primary analyses used ordinal logistic regression. Results: Asthma, bronchitis, recurrent ear infections, hay fever/allergies and speech problems associated with increased injury risk (OR range = 1.20-1.49 in bivariate ordinal logistic regression, ps < 0.01). Children with cerebral palsy had reduced injury risk (OR = 0.37, 95% CI = 0.15-0.91, p < 0.05). Most findings held after including demographic covariates in multivariate models. Conclusion: Because a range of chronic health conditions associated with increased injury risk, the causal mechanism behind relations between chronic illness and injury risk may not be disease-specific. Instead, factors related to having chronic medical conditions-not any particular condition-might contribute. Possible mediators include impaired family functioning, impaired peer relations, and familiarity with the health system/health-seeking behaviours. © The Author(s) 2011.