Electrophoretic deposition is the only technique available to fabricate nanoparticle thin films offering control on size distributions of nanoparticles on them. We describe the extensive efforts to understand this complex electrophoretic deposition process. One of the gaps in this research involves the size distributions achieved in the process. We address this particular issue by performing a lab scale experiment and providing a phenomenological model for size distributions. Nanocrystalline iron oxide particles were electrophoretically deposited from a stirred sedimenting suspension using different applied voltages onto silicon substrates. The as-deposited particles were further characterized by X-Ray diffraction and Transmission Electron Microscopy. For understanding the size distributions of these deposited particles, a phenomenological (lumped) model has been proposed. Two parameters have been considered in this model viz. applied electric field during deposition and effective viscosity of the medium in which particles were dispersed. There is good agreement between experiments and theory proposed through the model for a range of voltages. (C) 2018 Elsevier B.V. All rights reserved.