A model of electrocodeposition is developed for an unsubmerged impinging jet electrode system. The rate of particle incorporation has been described via the particle flux to the electrode, which was found to be mainly governed by convectional diffusion. The influence of gravitational and buoyancy forces was determined to be negligible for 50 nm nanoparticles, but influential for larger agglomerates. The probability for particles to be in the neighborhood of the electrode was used to fit the theoretical predictions to the experimental results for copper and nickel-alumina nanocomposite films made with a wide range of process variables. (C) 2008 The Electrochemical Society. [DOI: 10.1149/1.2993974] All rights reserved.