The aim of this presentation is to draw an overview of the existing regime of transboundary water governance in Mexico. The focus is given to the study case of the Rio Grande/Rio Bravo basin shared between Mexico and the United Sates, and of the Usumacinta River basin shared between Mexico and Guatemala. Both, transboundary river basins, share similar challenges and particular issues related to the borders they respectively define. However, both study cases show great differences concerning the ensemble of institutions and policy instruments of governance of water resources. How can best be framed each of the regimes of transboundary water governance? Some preliminary conclusions will be elaborated through a qualitative case study methodology.