We tested the hymenopteran parasitoid, Theocolax elegans, and transgenic avidin corn powder to determine if the individual or combination treatment would protect stored corn from infestation by both internal and external insects. We tested treatments of 0.3% powdered avidin corn, the parasitoid wasp, and the combination of the parasitoid plus 0.3% powdered avidin corn. Avidin corn powder had no detrimental effects on T. elegans. The parasitoid suppressed populations of the internal feeder S. zeamais. The avidin corn powder treatment had no effect on S. zeamais. For S. zeamais, the combination treatment was not significantly different from the parasitoid treatment. In contrast, T. castaneum were not suppressed by the parasitoid but were suppressed by the avidin treatment. C. ferrugineus density in the avidin corn powder-parasitoid combination treatment was significantly less than the control treatment. The total number of insects for all three species in the combination treatment was significantly less than the control or the parasitoid treatment but not the avidin corn powder treatment. The parasitoid-avidin combination treatment had the greatest percentage reduction for all three insect species and resulted in 78, 94, and 70% reductions in populations of S. zeamais, T. castaneum, and C. ferrugineus, respectively. The combination treatment of avidin plus the release of parasitoid wasps was superior to either treatment alone when applied to mixed populations of internal and external feeders.