The interest around polymer inclusion membranes (PIMs) has grown considerably in the past 6 years and, as a result, the number of research papers has risen exponentially. PIMs have been demonstrated to be useful for the selective extraction and recovery of numerous cations and anions and mimic the extraction properties of traditional solvent extraction and ion-exchange processes but have the advantage that extraction and back-extraction can be achieved in a single step. This review provides an overview of PIMs studies reported since 2005 and discusses extraction and transport studies according to the various base polymers, carriers, plasticizers and modifiers that have been used. Also discussed are the investigations of the PIM structure and stability in relation to other liquid membranes and the extension of the application of PIMs to separation problems involving analytical chemistry techniques such as flow analysis and analyte preconcentration. (c) 2012 Elsevier B.V. All rights reserved.