The electrodeposition of nickel-molybdenum alloys was studied on rotating cylinder electrodes. The current density, electrode rotation rate, electrolyte temperature, and species concentrations were shown to influence alloy composition. The mass-transport limiting species were identified for different operating conditions and electrolyte compositions in order to study the rate-limiting steps of induced codeposition. If the concentration of nickel in the electrolyte was much larger than that of molybdate the molybdenum content in the alloy increased with rotation rate. On the other hand, if the concentration of molybdate in the electrolyte was larger than that of nickel the alloy composition was found to be independent of rotation rate. These results were applied to the deposition of compositionally modulated Ni-Mo alloys exhibiting larger periodic variations in Mo concentration than hitherto reported.