A 49-d feeding study evaluated whether standard broiler diets prepared with Syngenta Seeds VIP3A transgenic derived corn grain had any unanticipated adverse effects on male or female broiler chickens as compared with diets prepared with nontransgenic (isoline) control corn grain. Two commercial lots of grain grown in North Carolina during the 1999 (NC 1999) and 2000 (NC 2000) seasons were included for reference purposes. Broiler growth was excellent with males reaching 3466 g and females reaching 2882 g at 49 d of age. Final BW of the VIP3A, isoline, and NC 1999 corn groups were within 21.1 g, whereas the NC 2000 group was 42.4 g lower than the lowest of this group. There was no overall corn source effect on adjusted feed conversion ratio (FCR) or mortality to 49 d of age. Carcass analysis demonstrated no differences in percentage yield due to corn source among males and females other than percentage wings in females. Comprehensive clinical chemical analyses of blood taken from representative birds at 49 d of age showed no differences due to corn sources. The transgenic VIP3A hybrid diets numerically supported the most rapid broiler chicken growth, the second lowest mortality rate and best FCR, without practical differences in carcass yield. The few differences found in this study were not unique to a given corn source but instead appeared to be distributed equally across the diet groups evaluated in the study. Although it was not clear whether small differences in performance were attributable to the transgenic corn per se or were due to possible slight differences in overall composition of the formulated diets, it was clear that the transgenic corn had no deleterious effects on broiler performance and carcass yield in this study.