Abstract: A process for producing a UO.sub.2 pellet comprising the steps of producing UO.sub.2 powder in accordance with the ADU (ammonium diuranate) method or the AUC (ammonium uranyl carbonate) method, forming a compact of said UO.sub.2 powder, and sintering the compact, wherein UO.sub.2 powder having a specific surface area of 5-50 m.sup.2 /g is used as a raw material in the compact forming step. At least one of chlorine or a chlorine compound (or bromine or a bromine compound) is added, in one or more of the UO.sub.2 powder producing step, compact forming step, or compact sintering step, in an amount such that the chlorine content (or bromine content) in the UO.sub.2 pellet amounts to 3-25 ppm chlorine (or 6-50 ppm bromine).