We compared the responses of the CERES and EPIC crop models, for wheat and corn, to two different climate change scenarios of different spatial scales applied to the central Great Plains. The scenarios were formed from a high-resolution regional climate model (RegCM) and a coarse resolution general circulation model, which provided the initial and boundary conditions for the regional model. Important differences in yield were predicted by the two models for the two different scenarios. For corn, CERES simulated moderate yield decreases for both scenarios, while EPIC simulated a decrease for the coarse scenario but no change for the fine scale scenario. Differences in the simulation of wheat yields were also found. These differences were traced to the contrasting ways in which the models form final yield, even though their strategies for simulating potential total biomass are similar. We identify the crop model type as an important uncertainty in impacts assessment in addition to the spatial resolution of climate change scenarios. ¿ 1999 American Geophysical Union