Aliasing due to undersampling is commonly present in all digital imagery. The imaging characteristics of the sensor, including optical blur, detector integration blur and electronic filter blur, determine the potential for aliasing in the digital images produced by that sensor. The actual extent of aliasing in any particular image depends on the scene spatial content. In this paper, we analyze the potential for aliasing in imagery from some current remote sensing systems, including the Landsat-7 Enhanced Thematic Mapper + (ETM+), Terra MODIS and EO-1 Advanced Land Imager (ALI). A metric is proposed and calculated for the aliasing potential of each sensor. The results show that the EO-1 ALI is the most susceptible to aliasing because of its relatively high MTF compared to that of ETM+ and MODIS. Real image examples are used to illustrate aliasing, including the use of aliasing to measure the sensor spatial response from certain types of targets.