The PEER members are mainly public funded national and European competence centres with scientific autonomy that are dedicated to environmental research with a predominant focus on interactions between man and the environment. The PEER centres are characterised by their interdisciplinary expertise, including a wide range of natural and social scientific disciplines, covering all fields of environmental sciences.

Currently, PEER consists of eight member institutes that together employ approximately 5,800 persons. The combined annual budget is about 600 Million Euro. The PEER institutes have a wealth of experience in participation in major international networks and programmes, and are actively involved in a number of projects funded by the EU's Framework Programme for Research and Development.