The purpose of the study is to conduct a comparative analysis of the existential concept of two outstanding philosophers of the 20th century - Martin Heidegger and Pavel Florensky. The study is aimed at identifying similarities and differences in approaches to existential topics, analyzing the arguments and understanding the various conclusions that these philosophers made in their works. The authors explore the main ideas, key concepts, criticism and prospects for the development of concepts, as well as the role of existential in the philosophical systems of the two authors. The article highlights the similarities and differences in the approach to the concept of existential, as well as the contribution of each author to philosophical thought. The study allows a better understanding of how these two concepts help to understand the philosophy of human existence and gain new perspectives for further research in the field of existentialism.