Corn plants (Zea mays L.) protected from damage by the coleopteran pest, corn rootworm (CRW), are under development by Monsanto. Insect protection was accomplished by the stable insertion of a gene encoding the Cry3Bb1 protein from Bacillus thuringiensis (B.t.). CRW protected corn plants will benefit corn growers and the environment by reducing chemical insecticide usage in corn and provide a more effective method of control of CRW. B.t. insecticidal proteins have over 3 decades of safe usage as biopesticides. They control larval pests, yet are safe to mammals, birds, fish and beneficial insects. Prior to commercialization of CRW protected corn varieties, protein safety data was generated to confirm the safety of the Cry3Bb1 protein. The test material used for safety studies was the Cry3Bb1 protein produced in and isolated from fermentation of Bacillus thuringiensis. Cry3Bb1 protein was shown to be have no toxicity in an acute oral toxicity test in albino mice dosed at approximately 3500 mg/kg based on body weight, food consumption and gross necropsy results. Cry3Bb1 protein was readily digested in 15 seconds in vitro using simulated gastric fluid. The Cry3Bb1 protein shared no significant sequence similarity to known allergens and toxins other than related B.t. insect control proteins. These data confirm the safety of the Cry3Bb1 protein, consistent with the established safety of related B.t. insect control proteins.