Structural aspects for the adsorption of urea at rhodium electrodes have been studied in perchloric acid solutions by combining electrochemical and in-situ FTIR spectroscopy experiments with single-crystal surfaces. Urea molecules adsorb at the rhodium electrode surface in competition with hydrogen and oxygenated species. Potential-dependent coverage changes, similar to those typically observed with specifically adsorbed anions, have been found to be structure-sensitive. Strong adsorption of urea molecules at the Rh(100) electrode surface allows the isolation of an irreversibly adsorbed layer that can be characterized in urea-free solutions. The infrared spectra collected for each rhodium surface show different adsorption bands for the adsorbed urea molecules that can be related to different orientations and/or adsorption sites. Urea molecules seem to adsorb always at the Rh(100) surface through the two nitrogen atoms with the C-O axis having a nonzero component perpendicular to the electrode surface. Only O-bonded urea molecules are detected at the Rh(lll) electrode surface. Potential-dependent changes for the intensity of the C-O stretching band can be understood on the basis of the tilting of the C-O axis at potentials higher than 0.50 V. In the case of the Rh(110) electrode, O-bonded and N-bonded oriented molecules predominate at low and high potentials, respectively. This change in the orientation of the adsorbed urea molecules can be related to the competitive adsorption of oxygenated species.