New Chromobacterium sp. strains were isolated from water collected from several localities in the eastern United States and were subsequently identified as the species Chromobacterium vaccinii Soby et al. Bacteria were cultured in a liquid medium and applied to artificial insect diets in the laboratory. All of the recently discovered C. vaccinii isolates tested were toxic to larvae of the seedcorn maggot, Delia platura (Meigen), but had little activity against larvae of the diamondback moth, Plutella xylostella (L.). None of the new isolates of C. vaccinii were toxic to adults of the red flour beetle, Tribolium castaneum (Herbst).