Absolute surface coverages (theta) of a series of tungsten-alumina catalysts prepared by the equilibrium adsorption method were determined by ion scattering spectroscopy (ISS) and low-temperature CO adsorption. The theta(CO) values for the W catalysts were very similar to those obtained with the ISS method, for a given W loading. A linear increase in W coverage with increasing W loading, reaching similar to 55% coverage for the 13.1% W solid, was observed. ?The calculated W cross-sections (22.0-24.5 Angstrom(2)/W) were in agreement with other reports in the literature. Due to the inherent limitations of each method, the combined use of ISS and low-temperature CO adsorption is recommended for estimating absolute surface coverages in tungsten-alumina catalysts.