Electrophoretic deposition (EPD) has been used to obtain self-supported alumina substrates from aqueous slurries. The uniformity of the final deposit is a function of the colloidal properties of the slurry. In this work, the conductivity and the solid content of the slurries are related to the deposition kinetics and the characteristics of the green compacts. The solid content is demonstrated to increase the experimental conductivity margins for suitable deposition. In addition, the more concentrated the slurry is, the lower the contamination of the deposit when metallic electrodes are used.