An improved extended Huckel molecular orbital study was conducted to predict the adsorbate configuration of ethylene and acetylene on Au(100) and Au(111) single crystal cluster surfaces at different simulated electric potentials. Three adsorbed configurations on both cluster surfaces were found for ethylene and acetylene, i.e. pi, di-sigma and mu-bridging species, whose relative contributions to the total organic surface coverage depend on the electric potential. Acetylene is chemisorbed on gold in a pi-bonded mode when a positively charged surface is simulated, whereas di-sigma and mu-bridging state are the most likely adsorption modes at negative electric potentials, the binding energies on Au(100) being larger than those of Au(111) clusters. Ethylene, on the other hand, is physisorbed on gold at equilibrium and positive electric potentials, however the chemisorption of the molecule is achieved when a negatively charged surface is simulated. Adsorption of ethylene at potentials below that of zero charge of the gold solution interface was observed. The anodic stripping of adsorbed ethylene at potentials lower than 0.20 V in 1 M H2SO4 (0.25 V in 1 M HClO4) exhibits two residues, in the double layer and in the gold oxide region. On the other hand, the adsorption of acetylene took place in two potential regions, one coinciding with the ethylene adsorption domain. and the other involving potential values positive to that of zero charge.