A diffusion-limited transient mathematical model for a lithium/air cell, with the air cathode pores flooded with an organic electrolyte, has been developed. During cell discharge, the cathode pore radius profile is reflective of the distribution of the lithium peroxide product in the cathode. The cathode pore radius profile has been predicted as a function of time, current density, oxygen gas pressure, and cathode thickness for an assumed initial porosity and average cathode pore size. Transient concentration profiles of the dissolved oxygen in the electrolyte were also determined. Capacities of the lithium/air cell were predicted and compared favorably with literature experimental results.