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Tile water quality and crop management data were collected for several years from different fields situated in an extensively tile drained and row cropped watershed of east central Illinois. RZWQM and DRAINMOD, were used to predict tile water quality as affected by climate and management practices for six of the eight field sites. Models were calibrated using two years of observed field data from corn-soybean rotation. Model predicted and observed NO3-N losses and Flow Weighted Average NO3-N Concentration (FWANC) in tile water were compared. For both models, the predicted daily and cumulative NO3-N losses in tile water mostly followed the same trend as observed data. Generally, DRAINMOD predicted peak NO3-N values were closer to the observed peak values than the RZWQM predicted peak values. The annual NO3-N losses in tile water were higher when corn year was a wet year and when fertilizer was applied either in the spring (pre-plant) of the corn year or in the fall of previous year. Both the models were capable of simulating the effects of crop rotation, fertilizer management practices, and rainfall on NO3-N losses and FWANC in tile water.