Fumonisins were monitored in corn grain collected from Bt hybrids grown in 107 locations across the United States in 2000-2002. Bt corn hybrids contain the Cry1Ab protein from Bacillus thuringiensis that controls European corn borers and other stalk-boring pests. Fumonisin levels were frequently lower in grain from Bt hybrids grown in field trials under conditions of natural (FACT trials) or manual insect infestation (university trials). Over three years of FACT trials, there were 126/210 comparisons when fumonisin levels in grain from control hybrids were >2 ppm, exceeding U.S. FDA guidance levels of 2 ppm for human food. Grain from Bt hybrids was at or below 2 ppm of fumonisins for 58 of the 126 comparisons. The use of Bt hybrids can increase the percentage of corn grain that would be suitable for use in food and feed.