Introduction: There are no epidemiological studies of Pediatric Out-of-Hospital Cardiac Arrest (POHCA) in Canada for at least 20 years. Understanding who has a POHCA event is key to prevention, education, and management strategies. Methods: In this retrospective cohort study, we used a validated algorithm applied to large hospital administrative databases to describe the epidemiology of pediatric (age 1 day to &lt 18 years) OHCA in Ontario, Canada, from 2004-2020, by pre-existing comorbidities, sociodemographic features, and outcomes. Results: The cohort included 1,839 unique pediatric patients with a POHCA event with a median age of 2 (0-12) years and 721 patients (39.2%) less than 1 year. Males accounted for 61.1% (n=1,123) of the cohort. Incidence was 4.2/100,000 with a gradual increase over the study period. Thirty percent (n=560) of the cohort lived in a neighborhood in the lowest income quintile, while 13.6% (n=251) lived in a neighborhood in the highest income quintile. Seventy five percent (n=1,380) lived in an urban setting. Seventy nine percent (n=1,444) first presented to a non-teaching, non-pediatric hospital following the POHCA event. The majority (n=1,533, 83.4%) of patients did not have significant comorbidities prior to the POHCA. The most common comorbidity was congenital cardiac malformation for 147 (8.0%) of patients. Three hundred and thirty-three (18.1%) survived hospital admission, and 132 (7.2%) survived to hospital discharge. Less than 6 patients had a subsequent POHCA in the year following the index event. Conclusions: This is the largest Canadian POHCA cohort and the first to describe incidence, comorbidities, and sociodemographic characteristics for this population. This is the first study to use a validated algorithm to create a POHCA cohort using large hospital administrative databases. We found a gradual increase in annual incidence over 17 years, POHCA mostly occurred in healthy children, and survival was lower than other reported cohorts. There were more than double the number of children with POHCA events living in the lowest income quintile neighborhoods compared to the highest income quintile neighborhoods. Most children with POHCA presented to non-teaching, non-pediatric hospitals first.