The separation of O2 from air, by a process in which the adsorption of N2 on a zeolite is combined with a subsequent O2 enrichment by permeation through a polymer membrane, was investigated. It was found that a higher degree of O2 separation from air is obtained with the combined pressure swing adsorption (PSA)-continuous membrane column (CMC) process than by either one of the two processes. With its good agreement between experimental and the numerically simulated data, the theoretical model for the CMC process was used to design a PSA-CMC apparatus with improved O2 separation. Based on the separation performances and materials that are already available, the possibility to develop a PSA-CMC process for the small-scale continuous production of 99.5% O2 from air was explored. The results obtained show that the economics of this process compare favorably with those of gaseous O2 supply from high-pressure cylinders.