Mixed ion-conducting ceramic membranes are promising in oxygen separationfirom air due to their infinite permselectivity. Hollow-fiber-shaped membranes can provide a high surface area for such an application. A mathematical model for a hollow-fiber La0.6Sr0.4Co0.2F0.8O3-delta (LSCF) membrane module for air separation was developed and a performance of the module at various operating conditions was studied theoretically. The simulation results reveal that the cocurrent is a better operating flow pattern than the countercurrent flow pattern. The vacuum operation on the lumen side of the membrane module is preferable to the elevated pressure operation on the shell side for achieving high oxygen productivity. A high vacuum level and a desired membrane area are essential to produce the pure oxygen and nitrogen simultaneously. Experimental results and kinetic parameters in the literature obtained from the LSCF membrane for air separation agreed satisfactorily with the theoretical solutions.