Objectives: To determine whether the rates of a first presentation to the emergency department (ED) for suicide-related behavior (SRB) are higher among children/youth permanently removed from their parental home because of substantiated maltreatment than their peers. To describe the health care settings accessed by these children/youth before a first SRB presentation to help design preventive interventions. Methods: A population-based (retrospective) cohort of 12-17-year-olds in Ontario, Canada was established. Children/youth removed from their parental home because of the above noted maltreatment (n = 4683) and their population-based peers (n = 1,034,546) were individually linked to administrative health care records over time to ascertain health service use and subsequent ED presentations for SRB during follow-up. Person-time incidence rates were calculated and Cox regression models used to estimate adjusted hazard ratios (HR) and corresponding 95% confidence intervals (CI). Results: After controlling for demographic characteristics and prior health service use, maltreated children/youth were about five times more likely to have a first ED presentation for SRB compared to their peers, in both boys (HR: 5.13, 95% CI: 3.94, 6.68) and girls (HR: 5.36, 95% CI: 4.40, 6.54). Conclusions: Children/youth permanently removed from their parental home because of substantiated child maltreatment are at an increased risk of a first presentation to the ED for SRB. The prevention of child maltreatment and its recurrence and the promotion of resilience after maltreatment has occurred are important avenues to study toward preventing ED SRB presentations in children/youth. Provider and system level linkages between care sectors may prevent the need for such presentations by providing ongoing environmental support. (Contains 1 figure and 4 tables.)