Expressions have been derived which describe the critical stress and pressure necessary to rupture oxide blisters which form on aluminum during the growth of corrosion pits. These expressions have been derived and evaluated for radial cracks in the oxide blister. The critical stress and corresponding pressure for rupture decrease with increasing blister radius and decrease with increasing crack length. The critical stress is independent of the ratio of oxide film thickness to blister radius, whereas the rupture pressure increases with this ratio. The critical stress is independent of Poisson’s ratio for the oxide film whereas the rupture pressure is weakly dependent on Poisson’s ratio for the oxide film.