Commercial cotton that is genetically devoid of epidermal terpenoid glands, i.e., glandless cotton, is more susceptible to damage from some insect pests, particularly the tobacco budworm, Heliothis virescens (F.), and bollworm, Helicoverpa zea (Boddie). A no-choice cage study was conducted in the field to determine if the level of resistance to tobacco budworm on glandless cotton could be improved with the addition of the genes (Bt) controlling expression of insecticidal proteins, 6-endotoxins, from the bacterium, Bacillus thuringiensis var. kurstakii. Larval survival was reduced to nearly zero on glandless TAMCOT CAMDE and glandless Stoneville 213 expressing the ë-endotoxins compared to an average of 24% survival on normally glanded Stoneville and 33% survival on glanded and glandless CAMDE that did not carry the Bt genes. Moreover, larval damage to squares and bolls was reduced to nearly zero on all normal glanded and glandless lines carrying the Bt genes and expressing the ë-endotoxin. We conclude that the Bt genes are a valuable genetic source to improve resistance of glandless cotton to damage from tobacco budworm.