Bt cotton refuge policies are derived accounting for previously ignored aspects of production and insecticide resistance. Results indicate that producers in Louisiana may experience significant losses and use considerably more conventional insecticides under current treated-refuge policy relative efficient treated-refuge policy. Results indicate that efficient untreated-refuge policy dominates efficient treated-refuge policy with respect to long-run producer profitability, annual profit volatility, conventional insecticide use, and end-period resistance-allele frequencies, and that the current untreated-refuge policy is efficient over 20-, 30-, and 40-year planning horizons.