The Cotton Wizard is an implementation of a cotton variety selection model intended to assist decision-makers (including producers, farm managers, extension specialists, and breeders) in variety selection. The program uses objective cotton performance test data available from state agricultural experiment stations. The decision criteria for variety selection are based on expected economic return (mean net revenue) of a variety and the variability of returns (coefficient of variation). Total revenue is calculated from lint price and seed price, and lint and seed yields. Lint and seed prices are determined by their respective quality characteristics. Adjustments are made for costs that may differ among varieties, such as planting seed cost (seed and technology costs), harvest and ginning costs, and herbicide and insecticide costs in comparisons of transgenic and conventional varieties. Users are provided with information on varieties—such as mean net revenue (total revenue less costs), variability in net revenue, and agronomic characteristics—to aid in the decision process. The Cotton Wizard is available as a Web application.