In the last years, precipitation data obtained from remote sensing have become potentially useful in agricultural and hydrological studies, acquiring greater importance in regions where climatic variables obtained by conventional methods are limited or nonexistent. Precipitation data are input variables for agro-hydrological models that simulate different scenarios in agricultural areas. Thus, this study compares the application results of the agrohydrological model SWAP during 2 years, 2008 and 2009, using rainfall data obtained by remote sensing and conventional methods. Simulations were performed with and with nosoybean cultivation, and the evaporation, transpiration, interception, runoff and bottom flux variables were evaluated. These simulations occurred in scenarios characterized by the predominant soil in the Taboao sub watershed, located in the Potiribu river watershed, Rio Grande do Sul state, Brazil. Major differences were found in runoff and bottom flux parameters. Estimates of the other variables, even with minor differences, also showed that the use of rainfall point data obtained by satellite at 8-km resolution transferred significant errors to the results of water balance.