The reported 'electro-catalysis' Of C-60-film-modified electrodes for the electrochemical oxidation of N-(4-hydroxyphenyl)ethanamide and salbutamol has been explored at boron-doped diamond and glassy carbon electrodes. Using both C-60-film-modified boron-doped diamond and glassy carbon as underlying electrode substrates no electro-catalytic response is observed using the target analytes but rather the C-60 serves to block the electrode surface. A common experimental protocol used by researchers in this field is to electrochemically pre-treat the C-60-film-modified electrode. The response of employing this electrochemical pre-treatment at both bare glassy carbon and boron-doped diamond electrodes using the target analytes reveals that no effect on the electrochemical responses obtained at the boron-doped diamond electrode whereas a slight but significant effect occurs on glassy carbon which is attributed to the likely introduction of surface oxygenated species. Consequently the previously reported 'electro-catalysis' using C-60-film-modified electrode is not due to C-60 itself being catalytic, but rather that substrate activation through electrode pre-treatment is responsible for the observed 'electro-catalysis' likely through the introduction of surface oxygenated species. This work clearly shows that substrate activation is an important parameter which researchers studying C-60-film-modified electrodes, especially in electro-analysis needs to be considered.(C) 2008 Elsevier Ltd. All rights reserved.