Since knowledge is an ontological reality, investigating the mode of existence of this phenomenon can significantly contribute to discovering its function. For this reason, ontological issues have always influenced epistemological perspectives. Given the profound transformations that the metaphysical foundations of Transcendent Philosophy have brought about regarding existence in general, and the issue of knowledge in particular, examining the extent to which the foundations of this school impact epistemological discussions becomes an unavoidable necessity. Accordingly, this paper, adopting an analytical–documentary method, seeks to identify the ontological approaches of this school that pertain to knowledge. The degree of influence exerted by its philosophical doctrines on key epistemological issues is evaluated. The findings show that the distinctive ontological perspectives of Transcendent Philosophy — such as the concomitance of knowledge and existence, the unity of the knower and the known, and the correspondence of realms — introduce fundamental changes in areas such as the value of knowledge, the possibility of knowing the external world, and the analysis of how error arises in cognition. Among these fundamental changes is the conclusion that the true essence of existence can only be apprehended through presential knowledge. These influences are expounded in detail under each of the metaphysical principles of Transcendent Philosophy.