Transgenic corn engineered with the Cry1Ab protein from Bacillus thuringiensis (Bt corn) is primarily used to control populations of European corn borer (Ostrinia nubilalis Hübner). We have collected field (Bt corn, non-Bt corn, and all other crops) distribution data in three 12 by 18 mile areas of southwestern Minnesota with high Bt corn adoption rates over the years 2002 to 2005. Farmers in these areas primarily grow corn and soybeans. We have used the field data to determine crop rotation rates of Bt corn and non-Bt corn fields from one year to the next at several spatial scales. We have also developed a quantitative resistance evolution model that includes a crop rotation parameter. The model results suggest higher crop rotation rates may decrease the amount of time it takes to evolve a resistant population for a pest that can disperse before laying its first generation of eggs, such as European corn borer. The field data suggest that Bt corn field rotation is high in our research areas at nearly all spatial scales and this would lead to shorter time for a resistant population of European corn borer to evolve.