3D woven carbon fibre preforms (~ 2 mm thickness) were impregnated with single or mixture of non oxide ceramic nanoscale powders in ethanolic suspensions using electrophoretic deposition (EPD). The measurement of the ζ potential of the suspension compared with its behaviour in sedimentation permits to conclude about the optimal concentration of surfactant necessary to get the most stable suspension. The experimental results were in agreement with the theoretical ones obtained using DLVO (Derjaguin, Landau, Verwey and Overbeek) theory. EPDs were carried out by applying a constant voltage between the 3D carbon fibre preform serving as deposition electrode and counter electrodes in graphite. The effect of the powder concentration on the rate and the quality of impregnation was studied. A qualitative model based on the experimental results and literature was then proposed. Experiments were not only carried out on raw 3D fibrous preforms but also on preforms with interphases. SEM and optical micrographies of fractured and polished sections of the infiltrated fabrics revealed that a quite high degree of infiltration (rates of impregnation estimated between 50 and 70 %) was obtained. At last, the composite was densified using spark plasma sintering (SPS).