Introduction:In many countries, integrated care has been implemented to improve the quality, efficiency and patient experience of services. Understanding how integrated care is adopted in different settings may give insights into where, how and why different components of the organisational design work. The aim of this article is to understand how and why integrated care for older people has been implemented in different contexts from the perspective of providers.Theory and methods:The study uses an innovative composite framework for the implementation of integrated care models, which posits that structural, organisational, provider, innovation and patient factors influence implementation along six dimensions of integration. A qualitative multiple case study was done of three cases in Québec using document analysis and semi-structured interviews of 28 providers. Descriptive comparisons and thematic analysis were performed.Results:Providers considered that structural (government policy) and organisational (mergers) factors highly influenced the implementation of organisational and functional dimensions of integration, at the detriment of clinical integration. Provider, innovation and patient factors mildly or moderately influenced the implementation of integration.Conclusion:Structural and organisational factors were necessary conditions for the implementation of administrative components of integration, with great variability in the implementation of some clinical components.