We explore the evidentialist challenge to religious belief, which is the challenge of showing that one has sufficient independent evidence in support of one’s religious belief. According to natural theology, we can meet this challenge through reason. We consider three historically prominent rational ‘proofs’ of the existence of God. The first, the ontological argument, tries to demonstrate that God’s existence follows from the very concept of God. The second, the cosmological argument, tries to demonstrate God’s existence by arguing that something must have brought about the existence of the universe, and that God is the only plausible candidate to play this ‘creator’ role. The third, the design argument, tries to demonstrate the existence of God by arguing that this is the only way to explain the complexity found in nature. Not everyone accepts the evidentialist challenge to religious belief. One proposal in this regard, known as fideism, argues that religious belief ought not to be subject to normal epistemic standards. In particular, fideists argue that religious belief is neither rational nor irrational, since it is a kind of belief that should be evaluated in terms of its own standards rather than the normal rational standards that are applied to non-religious belief. A second kind of proposal that rejects the evidentialist challenge is reformed epistemology. This approach defends religious belief by arguing that it is akin to perceptual belief, and so should be answerable to the same kind of epistemic standard. Since perceptual belief is not subjected to an analogous evidentialist challenge, so religious belief can be rationally held and amount to knowledge even though it fails to satisfy the evidentialist challenge.