In this article, the writer tries to cast light on reformed epistemology and its inter pretation of rationality which some figures of importance who supported Reformation put forward. He concludes his discussion by criticising the view that reformed epistemology experiences, to a lesser or greater degree, some sort of ralativism and fideism. From among the chief approaches to elucidating the relationship between reason and religion is the view known as "radical rationalism". This view manifests itself in a natural theology and is centered around reason. Natural theology presupposes that the rationality of beliefs based on dirine revelation will provide their condition of acceptability. The interpretation of rationality, which has always been given special attention by natural theologists' is referred to by the label "foundationalism" or "classical foundationalism" according to which rational statements or beliefs are either foundational or derived from foundational statements. In this interpretation, rationality and truthfulness run parallel to each other. In contrast with the classical foundationalism, reformed epistemology presents another interpretation of rationality.