The priority of existence is a basic principle that gives existentialist philosophy its character. Existentialist themes such as; value of human, meaning of life, freedom and responsibility, design and selection, understanding of individual and God and problem of values emerge from questioning this principle in high scales. The priority of existence, in this form, manifests the lifelike attitude towards existence and nihility, life and death. According to this, the world of human is not only a primal object of knowledge but also a world of existence with all its forms in which existence took place and experienced. In this article, what priority of existence than essence is and what results it brought out will be discussed: What does priority of existence than essence means? What does essentialist understanding represents and from which steps it has gone through? What kind of understanding of human and way of living the priority of existence than essence proposes? In the article, this and such questions will be sought for answer.