Abstract: There are current and near future satellite observing systems that, while not ideal for soil moisture measurement, can provide information for some conditions. These systems include the Special Sensor Microwave/Imager (SSM/I), the Tropical Rainfall Monitoring Mission (TRMM) Microwave Imager (TMI), and the Advanced Microwave Scanning Radiometer (AMSR). Of these instruments, AMSR holds the greatest ... promise for soil moisture. Soil moisture retrieval algorithms for AMSR have been proposed but they have not been rigorously evaluated. There are few data sets available for this purpose. This is a critical issue that needs to be addressed for both algorithm development and validation. For this reason, a joint project is being initiated between EOS IDS teams studying soil moisture processes and the EOS AMSR-E Science Team.