The analysis of Moroccan Islamist party PJD and Egyptian Islamist movement Muslim Brotherhood aims to achieve two separate but interconnected goals. First, the comparative method enables us to highlight varieties concerning the level of their behavioral and ideological moderation and the factors that brought them about, such as institutional design of the regimes and their ideological framework as well as the level of institutionalization of Islamists´organizations. Second, it enables us to empirically test the basic assumptions of the theory of participation and moderation that came to dominate the academic discourse on Islamist movements in the last decade.