The main aim of this work was to evaluate the simultaneous removal of Se(VI) and Cd(II) by anaerobic granular sludge in batch tests. The anaerobic sludge completely removed 10 mg/L Se(VI) and 20 mM (1800 mg/L) lactate within 1.5 d of batch incubation. After 7 d of incubation, 90.7% and 87.7% of 5 mg/L Cd(II) were removed by the sludge in, respectively, the absence or presence of Se(VI). Compared to experiments with autoclaved biomass, Se(VI) and total Se removal 98% and 70 was mainly due to bioreduction instead of adsorption onto anaerobic granular sludge. The increase in the protein and polysaccharide content of the extracellular polymeric substances (EPS) contributed to the adsorption of total Se and Cd(II). The predominant bacterial composition of the samples from the different treatments was similar. However, the abundance of genera in the microbial community gradually changed over the treatment time depending on the Se and/or Cd exposure. Se, as an environmental factor, had a positive impact on the dominance of the Methanosaeta, Syntrophobacter and Methanobacterium genera, while Cd had a positive impact on the dominance of the Methanosaeta genus. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.