The presented paper is a peer-review of plasma action on porous polymer membranes. Considering the plasma medium the discussion is split in two parts: i) the first shows some effects caused by action of non-polymerizing gases, i.e. polymer etching and/or alteration of surface character, and, ii) the second covers action of plasma reagents resulted in the deposition of polymer layers. The authors' attention is focused mainly on alteration of the membranepore structure and surfaces character. Both kinds of plasma can turn porous membrane to new porous species with different surface character and pore size. It is possible also to prepare solid membranes where deposited polymer completely plugs the pores. The presented discussion is illustrated by the results of the authors' own research on preparation of brand-new polymer membranes.