Corn Root Worm (CRW; Diabrotica spp.) is one of the most devastating pests of corn throughout the US corn belt and the Northeast causing annual losses of millions of dollars. A new variety of corn producing the Cry3Bb Bt toxin protects corn from CRW and will be planted on millions of acres worldwide in the next few years. Through basic laboratory assays and field sampling, the effects of this transgenic corn variety on the lady beetle Harmonia axyridis were investigated. Corn leaf aphids (Rhopalosiphum maidis) were collected daily in the field from CRW Bt, control and insecticide plots and were fed to H. axyridis in the lab for at least 16 days. The difference in H. axyridis survival was significantly different with 19 Bt aphid fed beetles surviving (N=30) vs. 29 of the control aphid fed beetles surviving (N=30; p=1.23x10^-3). Destructive visual sampling of corn plants in CRW Bt, control and insecticide treated plots from July to September 2002 revealed a significant difference in total coccinellid numbers (p<0.001) and H. axyridis numbers (p<0.001) with greater numbers in the control plots than the CRW Bt plots. No differences in aphid numbers were observed in the same treatments (p=1.0). ELISA results on the presence of Cry3Bb in corn leaf aphids will also be presented.