The electronic structure and chemical bonding of RhC, RhN, and RhO were experimentally investigated using anion photoelectron spectroscopy. Vibrationally resolved photoelectron spectra of RhC-, RhN-, and RhO- were obtained at two detachment photon energies, 532 (2.33 eV) and 355 nm (3.49 eV). Electron affinities, low-lying electronic states, and vibrational frequencies are reported for the neutral diatomic molecules. The adiabatic electron affinities are similar for the three molecules and increase slightly from RhC to RhO (RhC: 1.46; RhN: 1.51; RhO: 1.58 eV). The low-lying electronic states are rather simple for RhC, with its first electronic excited state occurring at 9400 cm(-1) above the ground state, whereas those of RhN and RhO are more complicated, with numerous closely spaced low-lying electronic states. Excited states of the anions were also observed for RhC- and RhN-. The trend of the chemical bonding from RhC to RhO is discussed based on the experimental results.