Kernel number, individual kernel weight, individual kernel volume, crude fat, crude protein, reducing sugars, starch content, amylose/amylopectin ratio and fatty acid composition were determined for six popcorn hybrids, grown in Colorado or Nebraska and harvested in 1997. The popcorn hybrids were A358W, 353W, BKH, 019, 1601 and 5501. Also, popcorn hybrids were categorized based on their popped color and popped shape as hybrid types, where A358W and 353W were white butter#y-type popcorn hybrids, BKH and 019 were yellow butter#y-type hybrids and 1601 and 5501 were yellow mushroom-type hybrids. Yellow mushroom hybrids showed signi"cantly fewer number of kernels than the white and yellow butter#y-type hybrids. The number of kernels per 250 g of popcorn hybrids at 14% moisture content ranged from 1454 to 2219. Individual kernel weight of the popcorn hybrids ranged from a low mean of 112.6 mg for hybrid 353W to a high mean of 172.0 mg for hybrid 1601. Individual kernel volume of popcorn hybrids containing 14% moisture ranged from a low mean of 0.130 cm for hybrid 353W to a high mean of 0.200 cm for hybrid 1601. The popcorn hybrids contained 3.8}4.6% crude fat, 8.1}10.5% crude protein, 0.07}0.23% reducing sugars and 61.0}67.9% starch, in which 27.0}28.5% of the starch was amylose. Individual kernel volume (size of the kernel) was correlated with starch content (r"0.84). Fat content was highly correlated with starch content (r"!0.82). Popcorn hybrids contained on an average approximately 12.6% palmitic, 2.0% stearic, 25.5% oleic, 58.4% linoleic and 1.5% linolenic acids, respectively. The major fatty acids in the popcorn hybrids were linoleic and oleic acids.