In this study, di-isononyl phthalate (DINP) was efficiently degraded by Sphingobium chungbukense KCTC 2955. The optimal conditions for DINP (100 mg L(-1)) degradation by S. chungbukense in a mineral salts medium were found to be pH 7.0, 30 degrees C, and stirring at 200 rpm. The maximum specific rate of DINP degradation was found to be concentration dependent, with a maximum of 4.12 mg DINP L(-1) h(-1). DINP was transformed rapidly by S. chungbukense, with the formation of monoisononyl phthalate (MIP) and phthalic acid, which subsequently degraded further. These results highlight the potential of this bacterium for removing DINP-contaminated waste in the environment.