Atomic force microscopy (AFM) has been used to study the morphology of an ultrafine gold-on-titania catalyst. By using TappingMode(TM) AFM (TMAFM) and SuperSharp silicon probes to minimize tip radius artifacts, we determined values for the average Au particle diameter and the gold loading in good agreement with high-resolution transmission electron microscopy (HRTEM) results. These results demonstrate the ability of AFM to characterize real supported metal catalysts with small metal particles (<5 nm) and low metal loadings, achieving resolution comparable to HRTEM, but in the ambient environment.