The article considers one of Heidegger’s statements presented in a letter to his friend K. Lowit dated August 19, 1921, in which he defines himself as a “Christian theologian”. The main existing perspectives on Heidegger’s “religiosity” being listed, the question arises, can we, and if so, in which sense, call Heidegger a “faithful Christian”? To answer this question, one needs to distinguish between “ontic theology” and “onto-theology”, the latter concept being very close to Heidegger’s own project of “fundamental ontology”.