This dissertation focuses on the adoption of the hypermarket in Finnish retailing and examines how major retail organizations experienced the transition from established practices into new logic of retail business, the large-scale retail trade. The research builds on DiMaggio and Powell’s (1983) analytical categorization of institutional isomorphic mechanisms, but utilizes more recent theorizations and insights of organizational institutionalism in the detailed theoretical framing. My research questions were as follows. How did Finnish retail organizations initially regard the hypermarket format? How did their stances change over time? To answer these questions, I examined the adoption of this format in terms of local decision-making, internal propaganda and corporate training. Each topic was discussed in a separate research article. The key findings of the research suggest Finnish retail organizations were initially strongly opposed to the hypermarket format and the principles of modern large-scale retailing in general. Key stakeholders of each organization resisted the hypermarket for different reasons, because the new practices did not fit the established lines of operation of the organizations and challenged their ideology- based principles. Thus, the top management worked actively to create support for the new practices and eventually for the adoption of large-scale retailing. Consequently, ideologically and structurally divergent organizations became increasingly similar (or isomorphic) as hypermarkets reached an institutionalized position. The findings demonstrate the significant role of individual actors in facilitating the increase of isomorphism, thus modifying the original idea of structural effects. Above all, the dissertation offers an alternative and complementary view of an important period in Finnish retail history.