The relationship between two things if one is another originator or creator, called causality. Although this concept is not specified to Medical Sciences and Epidemiology, the importance of this issue is more highlighted in the field of epidemiology. Causation is the most basic concepts in empirical sciences and is still under discussion because it is dependent on the basis of any scientific laws without acceptance something cease causality is impossible. With the increasing development of science as well as epidemiology, causality has found a broader concept and its application in analytical studies and logical interpretation of the results of this type of study, has a wider dimension. Due to developing new epidemiology courses at medical universities and increase the number of students, it is felt to talk more about the causality concept. In this review causality concepts in the humanities is overviewed, its history is briefly described, the causality of Medical Epidemiology and also Islamic religion is considered, then the causality framework, and models to interpret the conventional causality will be discussed.