Aix-Marseille University is a multidisciplinary university, with a variety of interdisciplinary programs and projects in research and education supported since 2012. Despite these achievements, we realized that pushing interdisciplinarity further required an encompassing approach to promote change. There was still a strategic undertaking that lacked to give substance to this priority as a whole. Indeed our current ambition is to implement a mainstreaming approach, making interdisciplinarity a lever for change in research, teaching, effective responses to societal challenges and organizational evolution. Therefore, on the basis of an inventory and consultation with the actors, a new Mission for Interdisciplinarity and Transdisciplinarity was created with four strategic objectives that we will present at this conference. These objectives are complementary and the Mission's ambition to address them simultaneously makes it original. Their level of achievement will be measured each year, in a "reflexive" perspective inspired by the quality approach. The Mission thus aims to transform reality as much as to produce knowledge about these transformations. As Kurt Lewin wrote: "If you really want to understand something, try to change it." The issue of structural obstacles to interdisciplinarity is indeed fundamental: we will explain how we intend to generalize interdisciplinary change within our University.