Resistance to pyrethroid insecticides in the corn earworm, also known as cotton bollworm, Helicoverpa zea Boddie, was a factor in reduced control of this pest in South Carolina in 1996 and 1997. Details are discussed of one pyrethroid failure in conventional cotton in Estill in 1996. Corn earworms collected from that field in September 1996 were resistant to cyhalothrin, cypermethrin and permethrin when tested in the laboratory. Resistance was confirmed by monitoring in 1997. Males captured in pheromone traps in Estill and nearby Ulmer in 1997 were resistant to cyhalothrin. Adults reared from larvae collected from cotton plants in Cameron and Holly Hill, 90 miles to the north, displayed high resistance. All moths trapped in the Pee Dee Region 180 miles to the north of Estill were susceptible. Strategies for controlling the pyrethroid-resistant corn earworm in conventional and transgenic cotton are discussed.