The influence of perfluorinated and hydrogenated surfactants on the mechanism of hydrogen evolution on gold electrodes in 1 M H2SO4 has been investigated from steady-state polarization curves and impedance data. The ohmic drop due to bubbles and the reaction inhibition, consequent on both the electrode surface masking by bubbles and the surfactant adsorption, have been separated and compared. The activity of surfactants decreases with the hydrophilic head in the order cationic > anionic > nonionic. Perfluorinated surfactants produce a lower inhibition than the hydrogenated ones on the electrochemical reaction which occurs in a Tafel kinetic regime, independently of the presence of surfactants.