One operational satellite remote sensing method for large-scale monitoring of root zone soil water status is based on the information available in satellite imagery that contains visible and near-infrared bands as well as -at least- one thermal band. The method is based on the METRIC/SEBAL approach for retrieval of regional distributions of evapotranspiration rates using Landsat, AVHRR, and MODIS imagery. The objective is to explain the optical/thermal method for root zone soil moisture monitoring, present validations, and discuss applications for hydrology.