The electrochem. properties of IrO2 and RuO2 nanoparticles, deposited on synthetic B-doped diamond (BDD) surfaces, are discussed. After a description of the prepn. procedure and the morphol. characterization of BDD/IrO2 and BDD/RuO2 samples, the dispersion efficiency of these oxides on BDD was estd. for different loading, using cyclic voltammetry. The electrochem. behavior of 1,4-benzoquinone/hydroquinone redox couple, oxygen evolution, and orgs. oxidn. reactions were studied at BDD/IrO2 samples; in turn, the chlorine evolution reaction was studied at BDD/RuO2 electrodes. Noncatalytic and catalytic models are proposed to explain the modification of the electrochem. behavior of BDD by low- and high-oxide loading, resp. [on SciFinder (R)]