The aim of this study was to determine the accuracy estimation of actual evapotranspiration by using Surface Energy Balance Algorithm for Land (SEBAL) in comparison with FAO-Penman-Monteith method in Landsat and MODIS images in Malayer County of Iran. In this study, Landsat 8 and MODIS images of 2013 were used. Result showed that there are not many differences between SEBAL and FAOPenman-Monteith methods in estimation of evapotranspiration. According to the aim of the study, result showed that MODIS sensor with high accuracy have calculated evapotranspiration more accurately than Landsat 8 by RMSE = 1.004 and MBE = 0.0033 respectively in surface temperature estimation which has great effect on estimation of the net radiation flux, soil heat flux and the sensible heat flux. On the other hand, according to low spatial resolution of MODIS sensor, we can conclude that this sensor has less value for zoning of evapotranspiration than Landsat 8 image according to the area topography and heterogeneous land uses
