Several species of phytophagous Pentatomidae (Nezara viridula, Acrosternum hilare, and Euschistus servus) were observed as pests on transgenic Bt cotton in South Carolina during the 1995-1997 growing seasons. Stink bugs damaged young bolls during mid-to-late season as adults migrated in from alternate hosts. Results from 1995-1997 indicated that control measures for stink bugs produced higher yields than no control. Treating with methyl parathion at a threshold of one stink bug per six feet of row provided adequate protection of developing bolls. Use of a ground-cloth is recommended in order to determine stink bug density per linear foot of row. We recommend insecticide treatment at a density of one bug per six feet of row. Careful attention should also be given to the percentage of young bolls damaged, and our data indicated that treatment might be necessary if more than 20% of bolls are penetrated in mid-to-late season. Bolls aged 18 days from white bloom were not significantly damaged by late instars (4th and 5th) which caused more damage than all other life stages.