This study determined the effects of early termination of furrow irrigation on yield of Deltapine's Bt-transgenic upland cotton variety NuCot33b. The experiment was conducted at the Texas A&M University Agricultural Research and Extension Center in Uvalde, TX, during the 1997 season. The irrigation termination treatments were as follows: termination at early bloom, termination at three wk after early bloom, and termination at early open boll. Early termination of furrow irrigation at early bloom and three wk after early bloom decreased lint yield by 45% and 16%. Data from plant samples showed that yield decrease resulted from the decrease in fruit retention and individual boll weight.