The adsorption equilibria of water vapor on Al2O3, zeolite 13X, and a zeolite X/activated carbon composite (Zeocarbon) were measured by a static volumetric method. The equilibrium experiments were conducted at (293.2, 313.2, 333.1, and 353.1) K and pressures up to 2.1 kPa for Al2O3 and 2.3 kPa for zeolite 13X and Zeocarbon, respectively. The experimental data obtained were correlated by the Aranovich and Donohue (A-D) and n-layer BET models.