The article deals with a comparative analysis of the ontological argument role in S. Frank’s philosophy of all-unity and in K. Barth’s theology of God’s Word. Studying the common and particular in interpretations of the ontological argument by Frank and K. Barth, the authors try to answer the question of how to distinguish the conceptual nature of philosophical and theological discourses. The articles and the position of Barth and the position of S. Frank in the ontological argument both explicate the overcoming an attitude of anthropocentrism (liberal theology) by Barth and subjectivism (modern philosophical tradition, starting with Descartes) by Frank. Therefore, their commonality can be traced in some original forms of theocentrism. In theological one by K. Barth and in philosophical-metaphysical one by Frank. Highlighting the same property of absolute reality, namely the impossibility to conceive its non-existence, they analyze that property in different ways within different discourses. Frank operates with a whole spectrum of philosophical strategies. Namely, along with metaphysical thinking in his works there is a methodology of dialogical philosophy, personalism and phenomenology. K. Barth, in his turn, in his antimetaphysical project uses such forms of philosophical discourse as dialogism (the event of Revelation understood also as transcending speech), existentialism (Christology described in categories of human communicative nature), neo-Kantianism (through Henrik Barth’s ontologization of sense’s and reason’s notions according to H. Kogen), German idealism (all aspects of K. Barth’s dialectics) and others. The ontological argument in the interpretation of Frank as well as in the interpretation of Barth should be attributed to the type of “non-classical” arguments.