A spreadsheet model was developed to predict the aflatoxin distribution among peanut lots in the market system from farmer stock marketing through storage, shelling, and blanching. The model calculates the aflatoxin distribution among lots after each major regulatory and processing stage in the market system from the buying point to the manufacturer. Model development is based on statistical and mathematical relationships derived from previous research on the effects of sampling plans and processing methods on the change in aflatoxin levels in peanuts. The USDA and the peanut industry can use the model as a tool to compare and evaluate the efficacy of proposed new regulations and processing methods on removing aflatoxin without actual costly implementation. The model also points out potential areas where information is missing and research is needed to better manage aflatoxin-contaminated peanuts. The model is used to evaluate the peanut market system where farmers' stock peanuts are chemically tested for aflatoxin.