This contribution proposes to investigate the disciplinary identities of researchers involved in interdisciplinary research in order to highlight its paradoxical nature which is revealed in their discourse about the way they perceive themselves and their own identity in the academic context. This paradoxical nature results in a tension between relatively stable and institutionally recognized disciplinary identities on the one hand and interdisciplinary hybrid identities that are still in need of recognition on the other. We address the complex relationship between the apparently stabilized disciplinary identity of researchers and their interdisciplinary research practices that lead them to redefine their identities in contact with other disciplines in a dynamic of multiple perceptions and representations. How do researchers demonstrate and represent their disciplinary –in some cases interdisciplinary or even undisciplinary– identity ? What are their relations with their institutional belonging and respective disciplines ? What are their academic and career paths that guide their practices ? By exploring these issues we propose a typology of different type-profiles of researchers who practice interdisciplinary research. The typology runs on a continuum from disciplinarity to undisciplinarity : disciplinary identity ; interdisciplinary identities expressed as thematic identity, hybrid identity, “interdisciplinary native” and “migrant interdisciplinary” ; and finally undisciplined identity. These reflections and typology are based on the results of a study on interdisciplinary research practices.