Background and Purpose: Since the entrance of Modern medicine in Iran, many controversies have occurred about scientificity of statements and concepts of traditional medicine between critics and advocates of this knowledge. The basic problem of these controversies is that before arguing whether this knowledge is science or not, it should be clear that which are the criteria of being science exactly? This is one of the fundamental questions in philosophy of science. Science philosophers have presented different criteria. The most important theory in this field in 20th century is the one that Thomas Kuhn has presented which asserts that the only criterion for scientificity is having "paradigm".

Materials and Methods: This paper, first of all by an exact examination on Kuhn's influential work in the philosophy of science (The structure of Scientific Revolution) will analyzes the theory and focuses on the concept of a paradigm, then explains the principles of traditional medicine and shows that this Knowledge possesses paradigm and thus is a science. Library based method has been selected for this research.

Result: The traditional medicine has its own concepts, rules, metaphysical principles and norms and therefore is science