A newly extended theory is presented on the role of polarization characteristics in determining the morphology of thick, polycrystalline metal electrodeposits. The theory is applicable to any system in which a single metal deposits. A simple galvanodynamic scanning procedure is more favourable than cyclic voltammetry, for predicting deposit morphology. The galvanodynamic technique represents an improved way of measuring accurately the nucleation potential and plating potential. According to the extended theory, these potentials can be readily related to the major metallographic structures of polycrystalline electrodeposits.