Due to the divergence on Information Architecture (IA) definition, it is analised how Phenomenology can improve the IA epistemological foundations. Based on Capurro’s work in Information Science theory, it is tried to characterise the IA as discipline from Information Science scope which focuses on information system structural design. Following it is analised the practiced definitions of IA, as well as the definition for Phenomenology focusing on Hessen’s interpretation for Phenomenology’s knowledge theory. It is discussed on this work that the Phenomenology can improve the field of IA building the definition of its object, the localization of the disciplines involved on knowledge question and the understanding of human being roles in Information System design.