The principal concern of this chapter is to provide those in the digital library community with the fundamental knowledge on the intellectual property rights and copyrights regarding multimedia digital libraries. The main objects of our discussion are the multimedia digital libraries with content-based retrieval mechanisms. Intellectual property rights are the only means for database designers to acquire their incentive of content collection and system implementation in database assembling. We outline the legal issues on multimedia digital libraries and retrieval mechanisms. As the protection of intellectual property rights is a critical issue in the digital library community, the authors present legal schemes for protecting multimedia digital libraries and retrieval mechanisms in a systematic, engineering manner.