Approximately 45% of Mississippi's 960,000 acres of cotton were planted to Bt-transgenic varieties in 1997. A field survey was conducted during late season to compare performance of Bt and non-Bt varieties. Bt-cotton fields sustained significantly less caterpillar induced boll damage than non-Bt fields, 1.86% vs 2.73%, and received fewer treatments targeting bollworms and tobacco budworms, 0.86 vs 3.14 foliar sprays per acre. However, Bt fields required more treatments for control of tarnished plant bugs and boll weevils. Other, less common pests that were observed more frequently in Bt-cotton included stink bugs and fall armyworms. Forty one percent of the Bt-cotton fields in the survey received at least one foliar treatment for control of bollworms. Supplemental foliar treatment of Bt-cotton fields for control of bollworms was more common in the Delta region of the state than in the Hills.