The article deals with the problem of the religious nature of the existential philosophy of N. A. Berdyaev and L. I. Shestov. A comparative analysis of their concepts in relation to the Christian interpretation of freedom has been carried out. It is shown that the concept of freedom can be expressed not only by its own semantic meaning (semantics), but also be reflected in the intuitive experience of existential cognition. Thus, the substantial freedom in the personal perception of N. Berdyaev and L. Shestov is opposed to the essence of the material-rationalistic understanding. In particular, from the standpoint of Berdyaev, freedom is comprehended through the creative combination of two principles: the Absolute Divine and the human. Whereas according to L. Shestov, freedom is achieved autonomously through the opposition of personal irrationality to the laws of logic. But both philosophers remain in the existentially incomprehensible field of knowledge of freedom. At the same time, the philosophers’ approaches are compared with the problems of the ontology of freedom, which they consider in the context of dogmatic and adogmatic thinking. Finding out the specifics of solving the problems posed, the author discovers that with regard to the existential-irrational ontology of freedom, Berdyaev focuses it on dynamic development. Whereas Shestov, on the contrary, turns to ontological freedom in an attempt to free the mind from self-evidentness, overcoming the laws of reason, thereby directing thought to the area of the irrational – to achieve pure religion and original religious freedom.