This study conducts a Cost-benefit analysis of dyke heightening in the Vietnam floodplain to explore some of economic issues associated with three interrelated aspects of the Mekong Development Programme (MDDP) in Vietnam, namely: (i) the implications of switching to more intensified agriculture and aquaculture; (ii) the effects of a more intensive use of agro-chemicals, and (iii) the construction of large-scale water control infrastructure. The study incorporates environmental and ecological economic perspectives in its analysis. The finding of strongly negative social and private net benefits as a consequence of dyke heightening led the study to the questioning of the economic effectiveness of the MDDP. It is intended that the work will hold interest for both decision-makers and local people concerned with water control infrastructures and intensified farming practises. It could also serve to provide an important lesson for other areas of the Mekong Basin that are planning similar development schemes.