This research study had the broad purpose of evaluating records of emergency department visits as a source of information for monitoring work-related injury and illness in Ontario. The primary objective of the study was to conduct a formal record linkage of emergency department records for the treatment of work-related injury and illness and workers’ compensation claims over the period 2004-2017. The main interest of this study is to describe the characteristics of the approximately 50,000 annual emergency department records for the treatment of a work-related injury or illness that do not link to a workers’ compensation claim.