Single-crystal Cu-Ni superlattices were grown on Cu(100) from an electrolyte containing 1.5 mol/liter Ni(SO3NH2)(2), 0.5 mol/liter H3BO3, and 0.009 mol/liter CuSO4. Specimens with modulation wavelength ranging from 2.6 to 70 nm have been produced. The films typically cover an area of similar to 2.5 cm(2) and are similar to 2.4 to 4.7 mu m thick. These materials should be helpful toward understanding the influence of modulation wavelength and orientation on the physical properties of metallic superlattices.