Crafting institutions related to the supply and use of irrigation systems require skills in understanding how rules, combined with particular physical, economic, and cultural environments, produce incentives and outcomes. If the users and suppliers of irrigation systems design their own institutional arrangements to cope with the physical, economic, social, and cultural features of each system, the variety of institutional arrangements could be immense. Examining specific rules of particular systems, however, is like focusing on specific blueprints of successful irrigation projects around the world. Recent theoretical and empirical work on institutional design has attempted to elucidate he core design principles used in long-enduring, self-organized irrigation institutions throughout the world. By ''design principle'' is meant a characteristic that helps to account for the success of these institutions in sustaining the physical works and gaining the compliance of generations of users to the rules in use. By ''long enduring'' is meant that the irrigation system has been in operation for at least several generations. Eight design principles identified in prior research are discussed and analyzed. ¿ American Geophysical Union 1993