Water for irrigation is increasingly becoming limited owing to increased demand from other uses such as domestic water, industries, and the environment which give higher economic and social returns. This is the case despite that irrigation remains one of the best options to meet future food demands. However there is wide the performance of irrigation projects in developing countries. Improving the water application of the scheme, which requires improving the management skills of the users, is one challenge to be tackled to ensure the sustainability of the schemes. This study aim was to undertake evaluation performance of Ariat and Nechilo small-scale irrigation schemes. Evaluate of irrigation performance of Ariat and Nechilo irrigation schemes using internal and external performance indicators. The most used internal indicators include conveyance efficiency, application efficiency, storage efficiency, water delivery performance and external indicators such as, irrigated agriculture Performance, water use performance, physical performance and output performance so as to recommend appropriate measures. The average conveyance efficiencies 77.4 % and 62.7%, respectively, for lined and unlined main canals of Ariat irrigation scheme while it was, respectively, 74% and 61% for lined and unlined main canals of Nechilo irrigation scheme. So, the study showed overall conveyance efficiencies were 42.2 % and 32.6%, respectively, for lined main canals of Ariat and Nechilo irrigation scheme respectively, the storage efficiency was 79.3% and 78% for Ariat and Nechilo irrigation schemes respectively. Output per unit irrigated area value of 4736.4$/ha and 5298$/ha were calculated Ariat and Nechilo irrigation schemes, respectively. Water productivity indicators such as, output per unit irrigation water supplied and output per unit water consumed value of 0.81$/m 3 ,1.53$/m 3 in Ariat and 1.13$/m 3 ,1.34$/m 3 in Nechilo irrigation schemes were calculated, respectively. The respondents believe that major problems that make the scheme to be inefficient were maintenance problem, water theft or unauthorized canal breaching in the scheme, water shortage, and water utilization conflict and they have a low level of ownership of the scheme. Generally, the overall performance of the scheme is considered poor. So, it is important to strengthen water user association, provide hydraulic flow measurements, routine maintenance, and creating awareness for the users to achieve good performance of the scheme. Keywords: Ariat, Nechilo, Performance, Efficiency, irrigation, Ethiopia