The present article embarks on dealing with the function of religion in different field. In the first part after elucidating the concept of the function of religion, the issue of the functions of religion on two social and individual level will be discussed.Under the first topic the individual functions including emotional knowledge –breeding and psychological or mental hygiene (giving meaning to life, removing the feeling of nostalgia, creating positive emotions), moral and behavioral functions (giving rational justification to morality, its support and practical guarantee) will be death. Under the second topic, hte social functions of religion including solidarity, social freedom, social justice, identity formation, and providing the ground for culture and civilization will be discussed.The second section of the article is about the possibility of finding a substitute for the functions of religion. In this regard, some have suggested philosophy, science and mysticism as substitutes for religion. However, this article will shed light on the shortcomings of these claims.The final part of the article will discuss pathology of religion's function. Some of pathological deficiency is viewed by some as alienation, superstition, objection against science and supporting the dominant power. These defects in religion's function will be analyzed in this article.