CCEDRRN is a collaborative network of 50 Canadian emergency departments who have been systematically collecting data on patients tested for SARS-CoV-2. It is the third largest COVID-19 research registry in the world, with over 200,000 patients enrolled since March 2020, and a current monthly enrolment rate of close to 3,000 patients. CCEDRRN data has been used to: develop diagnostic and prognostic risk scores for emergency department patients with COVID-19; to evaluate health system and public health responses to the pandemic; to validate diagnostic algorithms for venous thromboembolism in patients with suspected COVID-19; and to identify risk factors for post COVID conditions (long COVID).