Alvin Plantinga and other philosophers have argued that exclusive religious belief can be rationally held in response to certain experiences – independently of inference to other beliefs, evidence, arguments, and the like – and thus can be ‘properly basic’. We think that this is possible only until the believer acquires the defeater we develop in this paper, a defeater which arises from an awareness of certain salient features of religious pluralism. We argue that, as a consequence of this defeater, continued epistemic support for exclusive religious belief will require the satisfaction of non-basic epistemic criteria (such as evidence and/or argumentation). But then such belief will no longer be properly basic. If successful, we will have presented a challenge not only to Plantinga's position, but also to the general view (often referred to as ‘reformed epistemology’) according to which exclusive religious belief can be properly basic.