Preface by the Secretary-General of ICLA In accordance with the «Aims of ICLA» (ICLA Bulletin No. 26, March 1970) the Governing Board established in 1969 a Working Party to prepare an International Nomenclature System for Outbred Animals. The members were: Professor, Dr. A. Spiegel, Federal Republic of Germany, chairman.Dr. M. Festing, United KingdomDr. K. Kondo, JapanDr. R. Loosli, SwitzerlandMr. S. Poiley, U.S.A. The nomenclature rules, completed and approved by the ICLA Governing Board on 8 December 1971, are published herewith. I am convinced that this system will bring order out of the existing chaos. The system is an offer to the world laboratory animal science, particularly the breeders and users. Editors of scientific journals, catalogues, and indices all over the world are also encouraged to require and use animal stock identification by this system for outbred animals used in experimentation. The ICLA Governing Board would have preferred to have seen an international centralization of symbol registration. However, the ICLA Secretariat has not got the capacity necessary for such a task and some practical solution to the registration problem will have to be found by the Governing Board. A final aim should then be for ICLA to publish a comprehensive world list of breeder symbols at intervals. Oslo, January 1972 Stian Erichsen  Secretary-General