Corn engineered to produce the Cry3Bb1 protein from Bacillus thuringiensis Berliner (Bt) has provided unprecedented control for corn rootworm (Diabrotica virgifera virgifera Le Conte). However, accumulation and persistence of plant-produced Bt protein in soils may occur where Bt crops are repeatedly grown and residues of the crop plants are incorporated into the soil. If Bt protein is released into the soil rhizosphere, it may affect soil organisms. Studies were conducted to determine the effect of Bt or non-Bt corn roots and biomass on the weight and mortality of the earthworm, Lumbricus terrestris L. with different exposure methods and times. Enzyme-linked immunosorbent assay (ELISA) was conducted to determine if the Cry3Bb1 protein was present in the soil from the gut and excreta of earthworms. Results of these studies showed that there were no significant differences in weight and percent mortality of earthworms in soil planted or not planted with Bt and non-Bt corn or in soil containing ground air-dried biomass of Bt and non-Bt plants. Cry3Bb1 protein was detected in the soil from pots and the gut and excreta of earthworms exposed to Bt roots or biomass, whereas it was absent in soil from pot, the gut and excreta of earthworms exposed to roots or biomass of non-Bt corn. There was no significant difference in the amount of the protein recovered from pots or the gut or excreta of earthworms exposed to soils containing Bt roots or biomass for 12 or 33 d.