Operations Evaluation Study. "This report discusses six gravity irrigation schemes supported by the World Bank in the paddy lands of Thailand, Myanmar, and Vietnam. Its main objective is to assess: (i) the agro-economic impacts of these schemes at least five years after completion of the investment operations, and (ii) the influence of operation and maintenance (O & M) performance on the sustainability of those impacts. The finding that dominates the study has little to do with O & M. Offering poor economics and low incomes, these paddy irrigation schemes face an uncertain future. Improved O & M performance will not rescue them. In fact, the study finds that this causality is being reversed. As the uncompetitiveness of paddy farming drives the younger members off farms and the older members to stay behind and concentrate on basic subsistence crops, social capital will erode and O & M standards are likely to suffer. Based on the study of the six schemes, several recommendations have been made and grouped into the following general categories, then expanded on: (1) to sharpen the response to O & M failures; (2) to simplify the technology of infrastructure and operations; (3) to promote the transfer of management to farmers and their Water User Groups; and (4) to improve household earnings." Keywords: Gravity irrigation; Paddyland; Competitiveness; Agricultural productivity; Household income; Subsistence farming; Traditional farming; Farm management; Rural infrastructure; Agro-economic impacts; Operation & maintenance; Water user groups