Under international humanitarian law religious personnel must be protected against direct military attack. This basic principle, rooted in the humanitarian function of religious personnel on the battlefield, also applies to Islamic chaplains with the organized armed group “Islamic State”. However, the protected status depends on the exclusivity of the engagement in the work of the ministry. Against this background, the chapter assesses the (loss of) protection of the Islamic State’s religious personnel in Iraq and Syria. It distinguishes between such chaplains who are formally integrated into the organized armed group (IS-chaplains), and such civil chaplains who are not (IS-civil chaplains). By taking into consideration the Islamic State’s “holy war”-narrative and the data on their military administration, it will be argued that IS-chaplains are likely to also perform functions of religious propaganda and recruiting. Even in the light of international human rights law, such conduct can hardly be assessed as an exclusive engagement in the work of the ministry. As a result, the chapter argues that IS-chaplains, if such a non-exclusive function is sufficiently verified, can be legally subjected to direct military attack as every other ordinary member of the organized armed group. For the informally collaborating IS-civil chaplains, it will be shown that a protected status is granted quite independent of their religious function but via the general rules on the protection of the civil population. However, on the basis of assumed functions of IS-civil chaplains, the chapter concludes that (religious) recruiting by civilians, under certain circumstances, amounts to a direct participation in hostilities, again, resulting in the legal justification of direct military attack.