The South American Land Data Assimilation System (SALDAS) is an initiative that involves a collaboration between NASA/GSFC and the Centro de Previsão do Tempo e Estudos Climáticos (CPTEC: Center for Weather Forecast and Climate Studies), a division of the Intituto Nacional de Pesquisas Espaciais (INPE: Brazilian National Institute for Space Research) and the participation of the department of Hydrology and Water Resources at the University of Arizona. SALDAS is part of the NASA/GSFC Global Land Data Assimilation System (GLDAS) project. In order to increase the accuracy with which the participating Land Surface Models (LSMs) represent land surface processes over South America, retrospective (2000-2004) and real-time (2002-present) forcing datasets have been produced at 1/8 degree spatial resolution and 3-hourly temporal resolution. In an approach similar to that which the North American Land Data Assimilation System (NLDAS) project used, the datasets are derived from the ETA model data assimilation system at CPTEC (R-PSAS: Regional Physical-space Statistical Analysis System), supplemented by observation-based precipitation and radiation. The precipitation product is produced at CPTEC from TRMM derived precipitation combined with WMO surface daily observations and a sparse network of 3-hourly automatic surface stations. The downward shortwave radiation is derived from a radiative model GL1.2 from CPTEC. When either precipitation and/or radiation data is not available, CMAP and the radiation from the Air Force Weather Agency (AFWA) Agricultural Meteorology Modeling System (AGRMET) datasets are used. Validation and quality control will be performed using a variety of field campaigns in South America including LBA, SALLJEX and observations from surface stations.