Oxidative removal of a low concentration of CO from hydrogen was studied using a simulated moving bed reactor (SMBR) with 1wt'% Pt/Al(2)O(3) as a catalyst and adsorbent. Compared with an ordinary fixed bed reactor (FBR), SMBR showed higher CO removal when the ratio of the CO introduction rate to the active site moving rate (m(co)) was smaller than I. The presence of H(2) enhanced the CO oxidation performance of FBR, whereas it barely affected the performance of SMBR. Effects of mco, ratio of 0, introduction rate to active site moving rate (m(O2)), H(2) concentration and O(2) concentration on CO removal and CO(x) concentration in H(2) at the outlet of SMBR were investigated experimentally. The most important factor in order to enhance the CO removal was m(CO): CO was not detected at the outlets when mco was smaller than I. The most important factor in order to enhance the CO, concentration in H(2) at the outlet was m(O2): CO(2)-free H2 was obtained when m(O2) was larger than 1. H(2) concentration did not affect either the CO removal or the CO, concentration in H2 at the outlet. O(2) Concentration affected m(CO) and m(O2), which in turn influenced the CO removal and CO(x) concentration in H(2) at the outlet.