A leading brand in the market needs to continuously implement creative marketing strategies in order to defend its status and reinforce its market leadership in a rapidly changing market environment. In this case study, the authors examine how Binggrae’s leading brand ‘Yoplait’ formulated and implemented its marketing strategies in the Korean yogurt market in the face of strong challenges from its competition. Specifically, this case deals with how Yoplait responded to the competitors’ provocative marketing activities, how Binggrae renovated its own marketing mix strategies to defend Yoplait’s market leadership, and how it developed marketing communication strategies. Furthermore, the authors analyze the performance of Yoplait’s marketing strategies in terms of sales. The analysis revealed that Yoplait’s defense strategies were successful in protecting its market leadership from its competition. This case focuses on the success factors that enabled Yoplait’s defense of market leadership, and it discusses the ensuing implications and related problems that Binggrae is facing.