A growing recognition of the importance of farmer-managed irrigation systems has led public irrigation agencies to assist these systems by increasing the water supply and improving its reliability. The results of such assistance have been mixed, sometimes strengthening farmer organizations, at other times leading farmers to forego responsibility for the systems or even to bypass new structures altogether. Presented here are proceedings of a conference devoted to these issues. Ten papers on recent or ongoing research deal mostly with situations or programs involving public intervention in farmer-managed irrigation systems in Asia and Africa. Four papers written by irrigation agency staff address some of the problems agencies face in providing assistance to farmer-managed irrigation systems. Three final papers deal with the interaction among researchers and agency personnel, and how research is used to modify and improve agency programs to assist farmer-managed systems. Also included is a keynote paper, which reviews research conducted on farmer-managed irrigation systems over the past decade and suggests an agenda for future research. A major theme of current research is that, before intervening, agencies should understand how the existing farmer-managed systems are organized, the way they carry out irrigation activities, and the environment in which they operate. Since many countries lack information about the daily operation of farmer-managed systems, collaboration between researchers and agency personnel is strongly needed.