In 2000, Cotton Incorporated sponsored a bollworm monitoring program to assess the extent of pyrethroid resistance in bollworm (Helicoverpa zea) populations throughout the Mid-South/Southeastern U.S. Cotton Belt. Bollworm moths were collected and tested in Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, Missouri, North Carolina, South Carolina, Tennessee, Texas, and Virginia. Over 14,000 moths were bioassayed from May through October, 2000. Survival at the 5 µg/vial rate of cypermethrin ranged from a low of 0% to a high of 45.3% in Alabama during July. Thirteen states had greater than 10% survival during at least one month. This represents a 2.6-fold increase compared to data collected during the 1999 season and a 4.3-fold increase compared to data collected during the 1998 season. Survival at the 10 µg/vial rate of cypermethrin ranged from a low of 0% to a high of 34.2%. Five collections had greater than 10% survival during at least one month. This represents a 1.6-fold increase compared to data collected during the 1999 season and a 5-fold increase compared to 1998 data. These data suggest that bollworm populations throughout the mid-south/southeastern U.S. are developing resistance to the pyrethroid insecticides. Efforts to monitor pyrethroid resistance in bollworm populations should remain a priority for the development and implementation of future resistance management strategies.