Firmly embedded in the Islamic religious thought, practice and ethos, jihad (colloquially, 'Islamic holy war') is far from being an anachronism. In the aftermath of September 11, statesman, laymen and scholars and would be researchers have struggled to explain and understand why Muslims would be willing to participate in jihad. Is there some form of logic behind the decision? To what extent does rational instrumentalism determine the variation in the level of willingness to participate? Can socioeconomic status indicators tell us something about the profiles of the jihad participants and its prospective doers? Does identity politics have any significant bearing on the Muslims' level of participation? Based on empirical survey on Islamic religiosity in Indonesia and Iran, this study sets out to examine these pertinent issues. It delves into the various dimensions of religiosity, while explaining to what extent and how religious affection affects Muslim participation in jihad.