Cotton plants have been developed that control the major lepidopteran insect pests of cotton by the stable introduction of a gene encoding an insecticidal protein from Bacillus thuringiensis subsp. kurstaki. A comparison was made of the nutrient and antinutrient levels in the seed both to the parental variety and to published values for other commercial cotton varieties, as part of the safety and product assessment of these lines. Compositional equivalence confirmed the appropriateness of these cotton lines (531, 757 and 1076) for use in food and feed products. The insect-protected lines and the parental control were shown to contain levels of nutrients comparable to those of other commercial varieties. The levels of the antinutrients gossypol, cyclopropenoid fatty acids and aflatoxin in the seed from the insect-protected lines were similar to or lower than the levels present in the parental variety and reported for other commercial varieties. It is concluded that these analyses demonstrate that seed from the insect-protected cotton lines is compositionally equivalent to and as nutritious as seed from the parental and other commercial cotton varieties.