The kinetics of the reduction of bismuth uranate by toluene have been studied in micro-pulse and micro-flow reactors and in a thermobalance, at toluene mole fractions between 0.003 and 0.122 and temperatures between 455 and 527 °C. During the reduction the Bi2UO6 is converted into metallic bismuth and UO2. In the overall reaction rate both the chemical reaction rate at the surface and the rate of oxygen diffusion through the lattice of the solid play a role. A kinetic model comprising these two steps is derived. It appears that Bi2UO6 contains two types of lattice oxygen, viz, approximately 2% of a nonselective oxygen with D = 3 × 10-22 m2 sec-1 and a diffusion energy of activation E = 26 kcal mole-1, and a more selective oxygen with D = 3 × 10-20 m2 sec-1 and E = 63 kcal mole-1 (at 470 °C). Some evidence is found for bismuth uranate having a shear structure, the small amount of nonselective oxygen occupying positions in the shear planes.