A new recycle scheme of a membrane permeator was studied in order to produce a high purity less permeable component in the retentate stream. A part of the retentate stream was recycled to the permeate stream at the bottom of the permeator. The effect of retentate recycling on the separation performance was investigated both experimentally and theoretically for the separation of air, He/O-2 and He/N-2 mixtures. The effect of retentate recycle on the separation performance of a continuous membrane column was also examined. For all three gas mixtures, the less permeable component was always more concentrated with the retentate recycle than without it. The retentate recycling was more effective for the separation of a highly selective system as expected than for a less selective one (He/N-2>He/O-2>air). The experimental data agreed well with those calculated by the plug-flow model with the appropriate boundary conditions for the retentate recycle. The retentate recycle could be an innovative method for producing a high purity gas of the least permeable component from a mixture.