Synthesis of new poly(vinyl alcohol)-containing silver nitrate membranes is described. The membrane showed high olefin flux and olefin/paraffin selectivity. For this membrane, the effects of water saturation. silver nitrate content, total retentate pressure and permeate partial pressure on butene fluxes were investigated. For the facilitated transport of butenes and propylene in the membrane, we determined the mass transfer resistances due to complexation and decomplexation and thus obtained the "true" permeability which is independent of membrane thickness. Based on the mass transfer resistances and permeability, a transport model can be used to relate flux and selectivity to separation process conditions. Also investigated was the stability of the membrane.