Seven strains that can degrade nitrobenzene at low temperature were isolated from the sediments of a nitrobenzene-polluted river. One of the strains, NB-1, can mineralize 20 mg/L nitrobenzene completely from 2.5 to 35 degrees C with an optimum temperature of 25 degrees C. NB-1 was identified as Pseudomonas putida according to its morphology, biochemical properties, and 16S rDNA sequence analysis. The strain could tolerate and degrade 120 mg/L nitrobenzene within 175 h at 5 degrees C. It can be used for the bioremediation of nitrobenzene-contaminated environment.