MnOx/Al2O3-carbon nanotubes (CNTs) composites prepared by hydrothermal method were characterized by XRD, SEM, TEM, TGA, BET, XPS and H-2-TPR. Catalytic oxidation of chlorobenzene (CB) was conducted over the composites under gas hourly space velocity (GHSV) of 36000 h(-1) and CB concentration of 2800 ppmv. For the catalyst with approximately 25 wt% CNTs and 10 at.% Mn, CB removal efficiencies reached up to 83.3 and 97.7% at 150 and 300 degrees C, respectively. Moreover, no Cl species was detected over the used MnOx/Al2O3-CNTs catalyst implying that the release of chlorine element from the catalyst surface was facilitated by CNTs introduction.