This investigation demonstrates the rapid synthesis of a large quantity of uniform-sized gold nanocubes by an electrochemical method, using a surfactant solution and acetone. A redshift is observed in ultraviolet-visible absorption spectra as the shape of gold nanoparticles changes from spherical to cubic. The selected area electron diffraction patterns reveal that the gold nanocubes are single crystalline with lattice constant alpha = 4.068 angstrom. The nanocube edge is about 30 nm long. The gold nanocubes are truncated structures, as revealed by high-resolution transmission electron microscopy analysis. The effect of acetone addition on the shape of particles is also discussed. (c) 2006 The Electrochemical Society.