Pyrethroid resistance in Helicoverpa zea (Boddie) has been reported in Southern and Midwestern states during the last 17 years. In Indiana, however, commercial control failures were not reported until 2004, and small plot trial failures were not observed until the 2004-2006 growing seasons. To determine if these failures are due to the development of pyrethroid resistance, populations of H. zea from Vincennes, IN, Lafayette, IN and Collinsville, IL collected during the summers of 2006 and 2007 were reared in the laboratory and tested for resistance to pyrethroids. Larvae and adults from the established laboratory colonies were tested for resistance to bifenthrin, and field collected adults from Indiana were tested for resistance to cypermethrin. Larval toxicity trials also included a treatment with piperonyl butoxide to determine if the nature of resistance is metabolic or knock-down resistance. The LD₅₀’s and resistance ratios from these experiments and implications for H. zea control will be presented.