Most irrigation performance assessment studies have focused on internal indicators in which infield water use efficiencies were main target areas. Although such performance assessing parameters require collecting of intensive primary data which is in most cases time consuming and are challenging, their recommendations will be limited to infield water management improvement. IWMI has developed a methodology for assessing production, financial and water supply performances of either small or large scale irrigation schemes. The methodology applies internal and external indicators and requires very few data. The methodology can be applied for comparing different types of irrigation systems at different scales and also to evaluate a single scheme alone. This book attempted to introduce the concept of comparative performance indicators together with some process or internal indicators as a tool to ass two small-scale irrigation schemes of Ethiopia where availability of data is scarce. The outputs are very helpful for farmers, irrigation professionals, designers, researchers and policy makers.