Adult female bollworm moths were collected from various light trap locations in eastern North Carolina in late summer 2001. Female moths were allowed to oviposit, and upon hatch, 24 neonates from each female (F₁ families) were screened for growth rate on each of three diets: non-B. t., Cry1Ac, and Cry2Ab; B. t. diets contained 5.0µg toxin per milliliter of diet. Adults from F₁ families with growth scores in the highest (H) and lowest (L) quartiles were mated in 4 combinations, HxH, LxH, HxL, and LxL. Differences in growth rates of larvae from these crosses demonstrated that there is substantial quantitative genetic variation for resistance to both CryIAc and Cry2Ab.