A statewide pyrethroid resistance monitoring program for males of bollworm (Helicoverpa zea) was conducted from April to September of 2005, surveying twelve Texas counties. Moths were trapped near cotton fields using pheromone, Hercon LuretapeŽ with Zealure. Moths were collected early in the morning and assays were performed the same day. Vials were prepared in the Toxicology Laboratory, Department of Entomology at Texas A&M University, College Station, Texas and shipped as needed to Extension personnel. Vials were prepared using acetone only for controls, and cypermethrin (technical grade, 95.2% purity) at 0.15, 0.3, 1, 1.5, 2.5, 3, 5, 10 and 30 μg/vial. Moths from Burleson County, which had survivors at the 30 μg/vial dose in 2004, and moths from Nueces County, which had survivors at the highest dose of 60 μg/vial in 2004, were tested at additional doses of 60 μg/vial in 2005. One moth was placed in each vial and bioassays were evaluated after 24 hours. Moths were classified as alive, dead, or "knocked-down". Counties in Texas participating in the monitoring program were: Castro, Hockley, and Swisher Counties in the High Plains production region: Fisher and Mitchell Counties in the Southern Rolling Plains region; Ellis and Williamson Counties in the Blacklands region; Burleson County in the Brazos Bottom, Uvalde County in the Wintergarden region; Pecos County in the Far West region; and Nueces County in the Coastal Bend region. A total of approximately 5,280 moths were tested for all areas. Data from all areas in Texas was sent to Texas A&M University Toxicology laboratory and analyzed using Probit-PC, Probit and Logit Analysis and graphed using SigmaPlot. A baseline for susceptibility to cypermethrin in 2005 was established from a total of 432 moths tested from a susceptible laboratory colony obtained from the USDA-ARS laboratory in Stoneville, Mississippi. A LC50 value of .795 μg/vial and a LC90 value of 1.625 μg/vial were used to calculate resistance ratios. A LC50 value of 0.44 μg/vial obtained by Kanga et al. 1996, from studies in Burleson County in 1988, 1989, and 1993 was also used. A great degree of variability in susceptibility to pyrethroids was detected. The most resistant populations were from Nueces, Uvalde, and Williamson Counties while the most susceptible populations were from Fisher/Mitchell, Hockley, and Swisher Counties.