Abstract. In this paper, we propose a new content-based publish/ subscribe (pub/sub) framework that enables a pub/sub system to accommodate richer content formats including multimedia publications with image and video content. The pub/sub system besides being responsible for matching and routing the published content, is also responsible for converting the content into the suitable (target) format for each subscriber. Content conversion is achieved through a set of content adaptation operators (e.g., image transcoder, document translator, etc.) at different nodes in the overlay network. We study algorithms for placement of such operators in the pub/sub broker overlay in order to minimize the communication and computation resource consumption. Our experimental results show that careful placement of these operators in pub/sub overlay network can lead to significant cost reduction.