AMSR-E/Aqua surface soil moisture (LSMEM) L3 1 day 0.25 degree x 0.25 degree V001 is a global, 10-year (2002-2011) data set. It is created from soil moisture retrieved from passive microwave brightness temperatures measured by the 10.65 and 36.5 GHz radiometers on the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) sensor on the NASA Aqua satellite. The retrieval algorithm is based on Princeton's Land Surface Microwave Emission Model (LSMEM), a physically-based radiative transfer model, and serves as the core algorithm in the estimation procedure. To retrieve surface soil moisture, two unknowns, the soil moisture and the effective vegetation optical depth, are simultaneously solved from two radiative transfer equations in LSMEM, one for the 10.65 GHz horizontally-polarized brightness temperature and the other for the 10.65 GHz vertically-polarized brightness temperature. The land surface temperature required in the estimation procedure is estimated from the 36.5 GHz vertically-polarized brightness temperature, using a regression relationship. This soil moisture product does not include areas covered by snow, so the snow model is not described. Also, the atmosphere is assumed to have constant brightness temperatures; therefore, the atmosphere model is also not described.