This 42-day experiment was undertaken to compare the nutritional value of insect-protected corn event MON810 (YieldGard) and YieldGard x herbicide-tolerant corn event GA21 (Roundup Ready) to their nontransgenic controls as well as four different commercial reference corns, when fed to growing Cobb x Cobb broilers. A randomized complete block design was used, and each treatment was replicated with five pens of males and five pens of females with 10 broilers per pen. Broilers were fed approximately 55% wt/wt corn during the first 20 d and approximately 60% wt/wt corn thereafter. The corn component of diets fed to broilers was supplied entirely with grain from the eight hybrids included in the experiment. Final live weights averaged 2.09 kg/bird fed YieldGard corn and 2.15 kg/bird fed YieldGard x Roundup Ready corn and were not different (P > 0.05) from final weights for birds fed control or commercial corn. Feed conversion was not affected (P > 0.05) by YieldGard (1.72) or YieldGard x Roundup Ready (1.77) corn feeding when compared with the feeding of other corn diets. Chill weights, fat pad, thigh weights, and wing weights were not affected by diets (P > 0.05). Differences (P < 0.05) were noted for breast and drum weights across treatments. Broilers overall performed consistently and had similar carcass yield and meat composition when fed diets containing YieldGard (event MON810) or YieldGard (event MON810) x Roundup Ready (event GA21) as compared with their nontransgenic controls and commercial diets.