Layered double hydroxides (LDHs) have high anion exchange capacities that enhances their potential to remove anionic contaminants from aqueous systems. In this study, different Mg-Al and Zn-Al LDHs were synthesized by a coprecipitation method, with the products evaluated for their ability to adsorb selenite (SeO 3 2 - ) and selenate (SeO 4 2 - ). Results indicated the adsorption isotherm for SeO 3 2 - retention by Mg-Al and Zn-Al LDHs could be fitted to a simple Langmuir equation with the affinity of SeO 3 2 - on Zn-Al LDH higher than that on Mg-Al LDH. The adsorption trends for both SeO 3 2 - and SeO 4 2 - on LDHs were similar under the experimental conditions. The SeO 3 2 - adsorption was rapid and was affected by the initial SeO 3 2 - concentration. The quasi-equilibrium for 0.063 and 0.63 cmol/l SeO 3 2 - solutions was obtained within the first 30 and 60 min of adsorption, respectively. The maximum adsorption of SeO 3 2 - on Mg-Al LDH was higher than that of Zn-Al LDH and decreased with an increase in the LDH mole ratio of Mg/Al. The high pH buffering capacities and the SeO 3 2 - adsorption for Mg-Al and Zn-Al LDHs was a function of pH. Competing anions strongly affected the adsorption behavior of SeO 3 2 - with SeO 3 2 - adsorption increasing in the order: HPO 4 2 - <SO 4 2 - <CO 3 2 - <NO 3 - . The release of adsorbed SeO 3 2 - depended upon the type of competing anion in the aqueous solution. For example, with CO 3 2 - the adsorbed SeO 3 2 - could be desorbed completely from Mg-Al LDH. X-ray diffraction patterns indicated that d-spacing increased when SeO 4 2 - was adsorbed, but not with SeO 3 2 - adsorption.