The biodegradation of nitrobenzene by aerobic granular was investigated in this study. After cultivation in feeding-increasing form, nitrobenzene was degraded as sole carbon and nitrogen resource by aerobic granular sludge cultivated in SBR reactor and was not inhibited by nitrobenzene concentration up to 600 mg/L. Aeration time has a significant effect on nitrobenzene removal, especially at lower than 15 h. The highest nitrobenzene loading was 0.33 kg/(m(3)d) attained complete removal. Feeding time and shock loading had little effect on nitrobenzene removal. Micrococcus luteus, Bacillus sp., Pseudomonas sp., Comamonas sp., Acinetobacter sp. and Rhodococcus sp. are the main nitrobenzene degrading bacteria in the granular sludge. SBR with granular sludge was an efficient, reliable and stable process for nitrobenzene treatment. These results may provide a guideline for nitrobenzene wastewater treatment. (C) 2011 Elsevier B.V. All rights reserved.