The results showed that the overall model reliability was 56%. The mean absolute relative error (absRE) was 29%. The degree of accuracy and reliability varied with climate classes and nitrogen (N) -treatments. The largest bias occurred in dry years (RE = -25%) and the results were the most unreliable found in N-0 treatment (reliability = 32%). There was more than 69% probability that the input-data-induced uncertainties were limited to less than 20% of absRE. This study concluded that the EPIC model is reasonably reliable for studying the effects of climate change in the U.S. Great Plains and input-data-induced uncertainties were limited when compared to model structure/parameter related errors.