In the main valleys and plains rapid economic and social development over the past several decades has altered the use of land and water in ways that profoundly affect vulnerability of households, firms and regional economies to individual flood events and longer-term changes in flood regimes. Disaster risk reduction measures usually involve structural interventions in the form of walls, channel modification, drains, pumping stations, diversions and storage dams. Institutional measures, like early warning systems, community capacity building, insurance and compensation schemes may also be supported and promoted to reduce risks of damage and burdens from losses. In this paper we review instances and conditions under which flood management policies, measures and practices in the greater Mekong region, intended to reduce risks, appear to have shifted risks onto already vulnerable and disadvantaged groups. We classify these observations into six mechanisms through which risks may be redistributed. This analysis highlights the importance of public participation and negotiation in handling various risks associated with flood management, and, conversely, why purely technical, expert-driven, approaches to flood disaster management are unlikely to succeed in reducing the risks of flood disasters.