The aim of this paper is to summarize recent progress on full interpenetrating polymer networks (IPNs) and semi-interpenetrating polymer networks (semi-IPNs) as proton-conducting membranes for use in fuel cells. IPN materials possess a series of unique properties, by virtue of which they represent particularly suitable candidates for this application. Although IPNs have been thoroughly studied for 50 years, fundamental research and/or applications of IPNs in the field of fuel cells remain little explored. A short review summarizing investigations carried out on these particular materials as protonic membranes could prompt the development of these highly promising architectures in this field, the environmental importance of which is growing exponentially. (C) 2010 Elsevier B.V. All rights reserved.