Mixed Reality Learning Games (MRLG) provide new perspectives in learning. But obviously, MRLG are harder to design than traditional learning games environments. The main complexity is to cope with all the difficulties of learning design, game design and mixed reality design at the same time, and with the integration of all aspects in a coherent way. In this paper, we present existing tools and methods to design learning games or mixed reality environ-ments. Then, we propose a model of MRLG design process. In the last part, we present an authoring tool, MIRLEGADEE, and how it supports this process.