Foundationalism is the most ancient theory on epistemic justification. This theory employs the metaphor of a building. Every building consists of two parts: foundation and superstructure. Superstructure always relies on the foundation. Man"s beliefs are shaped in a similar fashion, i.e., some beliefs are foundations and some are superstructure. This article first shows the principles and different kinds of foundationalism and then discusses the most important argument of its supporters, namely, infinite regress argument, and finally shows that from this argument point of view the coherentists are in a better position than foundationalists.