Abstract Studies by cyclic voltammetry of an ordered Rh (111) electrode in various aqueous electrolytes are reported. These include solutions containing components which interact weakly with the rhodium surface, such as perchloric and sulfuric acid, and those containing strongly interacting reagents: halide anions and silver cations (to form underpotentially deposited silver adatoms). Qualitative similarities between the (111) surfaces of platinum and rhodium are emphasized. Such similarities are particularly well exposed by analyzing the effects of the electrochemical treatment on the voltammetric profiles in various systems. The nature and extent of these effects provide evidence that order/disorder transitions of the Rh (111) surface are as important in the surface electrochemistry of this metal as they are in studies of well-defined platinum electrodes. We also observed that halides are more strongly bonded to rhodium than to platinum. Likewise, three underpotential deposited monolayers of silver were observed on Rh (111) vs. two on Pt (111). This shows that the surface activity of rhodium towards the solution reagents is higher than that of a Pt (111) electrode.