This article is based on a thesis that examined open innovation in the Brazilian cosmetics sector and its relationship with knowledge integration, comparing less open and more open firms. The ability to integrate knowledge is related to competitive advantage, and this study sheds light onto OI at each different firm. The main findings show that, different levels of openness in innovation, demand firm-specific mechanism for KI. Also, openness increases complexity in management. The understanding of how firms select their knowledge for appropriation and differentiation is also considered. The Brazilian cosmetics market was chosen because it occupies the 3rd position in the world´s ranking and this industry is under researched. A cross-case comparison is used.