Participatory management of water resources presents special problems because the interests of the farmers located at the head and the tail of a canal do not match and government machinery is usually the sole arbiter. This paper attempts to quantify the benefits of participation in irrigation systems in Cambodia through a survey of 50 irrigation projects in the country. We find that participation by stakeholders does improve project performance. We find that even in the absence of a coherent state bureaucracy, state-society synergy can exist and participation can lead to better project outcomes.