OBJECTIVES: Recent research has focused on the effects of legalization on cannabis-related emergency department visits, but the considerable healthcare costs of cannabis-related hospitalizations merit attention. We will examine the association between recreational cannabis legalization and cannabis-related hospitalizations. METHODS: A cohort of 3,493,864 adults from Alberta was examined (October 2015-May 2021) over three periods: pre-legalization, post-legalization of flowers and herbs (phase one), and post-legalization of edibles, extracts, and topicals (phase two). Interrupted time series analyses were used to detect changes. RESULTS: The study found an increase in hospitalization rates among younger adults (18-24) before legalization, yet no increased risk was associated with cannabis legalization, for either younger (18-24) or older adults (25+). CONCLUSIONS: Clinicians should be aware of the increased risk in younger groups and may benefit from early identification and intervention strategies, including screening and brief interventions in primary care settings.