Nanoparticles of ruthenium disulfide supported on silica have been characterized by high resolution transmission electron microscopy. Lattice resolution images were obtained and provided the morphology of the RuS2 nanoparticles. The interpretation of the atomic resolution images was performed with the help of image simulations, which enabled the atomic columns to be correctly positioned and the thickness of the nanoparticles to be estimated. Several surface planes. such as (200) or (111), which are supposed to present different catalytic activities, have been identified.