This publication presents both an overview and detailed information on more than 150 experimental facilities being used for developing and deploying innovative liquid metal cooled (sodium, lead and lead–bismuth) fast neutron systems, both critical and subcritical. Facilities under construction and those in operation are considered. It is expected that by providing the end users with detailed information on existing and future experimental facilities able to support innovative liquid metal cooled fast neutron systems, the publication will facilitate cooperation between organizations and knowledge transfer. An overview of the existing and future experimental facilities is presented in the body text of this publication. The profiles of all facilities in the form of individual papers are available on the attached CD-ROM and in the related on-line database maintained by the IAEA Catalogue of Facilities in Support of Liquid Metal Cooled Fast Neutron Systems (LMFNS Catalogue).