The properties of poly(ethylene) terephthalate track membranes (PET TM) subjected to effect of plasma of the RF-discharge in air have been investigated. The influence of conditions of a plasma treatment on the surface properties and hydrodynamic characteristics of the membranes has been studied. It has been found that the effect of the air plasma on the membranes studied results in a formation of asymmetric track membranes with a higher flow rate; the structure and chemical composition of their superficial layer are changed. It was shown that the presence of the modified layer on the membrane surface caused changing in their hydrodynamic characteristics-the water permeability of the membranes, processed in plasma, in a greater degree depends upon pH of a filtered solution.