Strains of Aspergillus flavus that do not produce aflatoxins (atoxigenic strains) are used to competitively exclude aflatoxin producers and thereby limit aflatoxin contamination of cottonseed. Influences of atoxigenic applications extend over multiple years. This suggests that atoxigenic strain applications to cotton might serve to reduce contamination of crops rotated with cotton. During 2003 tests were initiated in several regions of South Texas to evaluate the use of atoxigenic strains to limit aflatoxin contamination in cotton-corn rotations. Results to date suggest that atoxigenic strain applications can reduce the aflatoxin-producing potential of fungal communities in this region.