The growth and structure of thin electrodeposits of several metals on single-crystal substrates have been studied by means of electron diffraction and electron microscopy. Deposits of copper on nickel, nickel on copper, and gold on copper show a highly perfect orientation at all thicknesses up to 1000 Å. All deposits studied were continuous for thicknesses greater than 50 Å. Gold deposits of 15 Å were discontinuous on the (111) face. Few growth twins were found, but double positioning structures occurred in both nickel and gold films. Evidence for the enhanced nucleation of copper deposits on substrate twins was found.