Theme of this thesis is psychology of religion and Sigmund Freud. Psychology of religion is modern science which can also be studied as empirical science. The main idea of this thesis is to represent how scientists, but mostly Sigmund Freud, are explaining religion. Although through the thesis you can read other scientists opinions such as C. G. Jung, Adler, Keilbach, their opinion will be explained and compared with similarities and differences with Freud’s opinion. At the beginning of the thesis it is explained who Freud is, general informations about his life and what were the reasons that made him, an atheist, to study religion. Talking about Sigmund Freud and his work, it is impossible to avoid his psychoanalysis which he also used in his research of religion.American psychology of religion is explained in more detail as a separate entity of what European scientists are representing. In conclusion we can see that what religion means to each scientist is often connected to the fact of whether is he a believer or not. Psychology of religion is represented as very controversial part of psychology and science in general because it has a lot of factors which are influencing point of view and are very disputable. The thing which is important to highlight is that no matter the difficulty of the exploring it, psychology of religion is very important as science and there is a need for many more researches in order to explain unresolved theories. Regardless of the part of religion that has been studied, it by it’s nature leaves a mysterious section and it is on every believer alone to decide with their free will how and in what will they believe in.