The Second International Workshop on Poultry Genome Mapping, meeting at the 1994 Conference of the International Society for Animal Genetics, and the Poultry Committee of the USDA National Animal Genome Research Program have approved a new set of guidelines for poultry gene and allele symbols to replace the guidelines published previously. The new guidelines are a modification of the human gene nomenclature guidelines and are designed to facilitate the naming of loci detected by molecular probes and electronic publication in on-line databases. Authors and journal editors are strongly encouraged to adopt the new nomenclature guidelines. Comments and suggestions are welcome. The complete text of the guidelines can be accessed on the World Wide Web. The home page addresses are: http://www.ri.bbsrc.ac.uk/chickmap/ChickMapHomePage.html for the ChickMap home page, Roslin Institute, UK and http://poultry.mph.msu.edu/ for the Department of Microbiology, Michigan State University, USA. The home pages will contain updates and changes in the guidelines. The home pages also provide access to CHICKBASE, a chicken genome database, which will have a listing of old and new gene symbols. A World Wide Web browser is required for access. The guidelines can also be obtained from LB Crittenden (e-mail: slcritte@facstaff.wisc.edu). The International Poultry Gene Nomenclature Committee comprises the authors of this letter to the editor.