The need that emerged in Development Studies to trespass across disciplinary boundaries is discussed. An interdisciplinary characterization of Human Sustainable Development is sketched. Some attempts at the University of the Republic in Uruguay to foster related work that connects sciences and natural sciences are briefly described. This work spans research, teaching, institutional building, and university reform. It has been affected by the difficulties of pursuing interdisciplinary work when the growth of knowledge promotes specialization and academic structures are shaped by disciplinary concerns. Nevertheless, emergent lessons from the experience reported here suggest that trespassing across disciplinary boundaries in Development Studies may contribute significantly to fostering interdisciplinarity.