• While religion is a part of every culture and is entangled in many facets of the lives of those who are religious, the scientific study of religion and the Religious Studies discipline are fairly new, only developing in the mid to late nineteenth century. One of the contributions that the scientific study of religions has made is the development of different approaches for classifying religions. As a multidisciplinary field, Religious Studies and the classification of religions has been influenced by philosophy, psychology, history, sociology and anthropology. This study, using the domain-analytic paradigm, traces the development of the Religious Studies discipline and the classification of religions, analyzes the epistemological assumptions behind the prominent approaches used to classify religions and briefly examines their relation to the Library of Congress, Dewey Decimal and Universal Decimal classifications.