The U.S. share of world Bt cotton acreage has fallen from virtually 100 percent in 1996 to 75 percent in 2000. Three scenarios were examined simulating low, moderate and high impacts of foreign Bt cotton adoption in 1999. Increased production lead to a decrease in the world price of cotton ranging from 0.8 to 2.5 cents. Rising commodity program payments mitigated nearly all of the negative impacts of falling prices on U.S. producers. For U.S. cotton producers, the net economic benefits of Bt technology (benefits of domestic adoption minus the losses from overseas adoption) remain large. This may change, however, if the Adjusted World Price rises above the loan rate and if foreign adoption continues to grow relative to U.S. adoption.