The carboreduction of UO₃ into UO₂ has been studied with an excess of carbon (C/U=3 mole ratio). The results of thermogravimetric (TG) studies, X-ray diffraction (XRD) and SEM reveal that the carboreduction depends upon the texture and the physical mixture of the precursors UO₃ and carbon. Indeed, optimal carboreduction was obtained with an improvement of UO₃ and carbon grains contacts during the reduction. The preparation of the mixture (UO₃ + 3C) has been optimised by a slight manual grinding.