In recent years, the most popular topics related to the environment are climate change and water problems. Especially, studies about the impacts of climate change on water resources increase dramatically. One of the important problems related to climate change will be the impact of climate change on water resources in the future. Therefore, the possible effects of climate change on water resources must be determined. In this study, the possible effects of climate change on evapotranspiration, which is one of the most important losses from water resources, were analyzed for three cities of the Thrace Region (Edirne, Kırklareli, Tekirdağ). Past and future status of reference evapotranspiration were calculated with commonly used eight different methods and future projection of evapotranspiration was compared with past data set. The past situation was demonstrated by using actual data obtained from meteorological stations for the period of 1975-2010. The future projection was estimated for 2015-2040 by using ECHAM-5 model data in the framework of the A1B scenario. As a result of the study, in the framework of eight methods, it is determined that evapotranspiration would increase between 9 and 14% in the future.