Regionalization is arguably the most significant health reform in Canada since medicare. Although a majority of provinces continue to have regionalized systems in Canada, the policy is more contested today than it was a decade ago. Since Ontario's implementation of local health integration networks (LHINs) in 2006 and Alberta's elimination of regional health authorities (RHAs) in favour of Alberta Health Services in 2008, Canada has had differing approaches to regionalization. However, due to the centralization of physician budgets in provincial health ministries, primary care has not been integrated into any regionalization model in Canada. This factor has severely constrained the performance of RHAs and their ability to meet their respective legislative mandates. Moreover, the lack of research on regionalization has meant that provincial governments are working from an extremely limited evidence base on which to make critical decisions on the structuring of health systems in Canada.