Abstract: The aim of this study was to assess the impact of the water users related to management-operation and maintenance services carried out by Water User Associations (WUAs) in the Great Menderes basin irrigation schemes. Irrigation schemes of basin are operated by WUAs, an user organization and consist of 4 schemes, namely Nazilli, Akçay, Aydın and Söke. In order to investigate the opinion of the water users in general, a survey was carried out, using the random sampling methodology. A questionnaire considering 5 different topics was used to analyze the management, operation and maintenance performance of the WUAs. The user’s general opinion is that the turnover of the irrigation infrastructure to the WUAs has had a very positive impact.