The direct microwave sintering of natural uranium dioxide (UO₂) pellets at bulk scale is first time successfully demonstrated. The process of the microwave sintering is carried out at 1700 °C, 6h in reducing atmosphere with a sintering cycle spanning over 31h in an indigenously designed and developed sintering set-up deploying 2.45 GHz microwave radiation. The process is demonstrated for obtaining defect-free pellets (devoid of cracks and any plasma induced edge/surface melting or burnouts) in bulk quantity consisting of a batch size of 3 kg (500–550 pellets). The sinter density of pellets was found to be uniform and in the acceptable range of 92–96%TD for nuclear fuel. The comparison of optical microstructures prima facie indicates that the UO₂ grain size is smaller in microwave sintered pellets (5–20 μm) as compared to conventionally sintered UO2 pellets (10–40 μm) under identical parameters. The axial and the diameteral shrinkages during densification were observed to be 18–20% which are comparable to the conventional sintering. The microwave sintered UO₂ pellets has O/U mole ratio as 2.002. The process is consistent and easily up-scalable to sinter large size of batches so as to meet the industrial scale demands.