The ICSP, formerly the International Committee on Systematic Bacteriology (ICSB), is the body that oversees the nomenclature of prokaryotes, determines the rules by which prokaryotes are named and whose Judicial Commission issues Opinions concerning taxonomic matters, revisions to the Bacteriological Code, etc.

In the 19th century and the first half of the 20th century, bacteriologists tried to follow the provisions of the Botanical Code of Nomenclature, because bacteria had traditionally been considered fungi, the Schizomycetes. Methods of study were, however, very different. Also, much emphasis had to be put on cultural characteristics, so that type cultures were of critical importance. Type cultures are not permitted under the Botanical Code; therefore, at the First International Congress of Microbiology in Paris in 1930, proposals were made for bacteriology to establish its own Code of Nomenclature. A committee under the able guidance of the American bacteriologist R. E. Buchanan began work on this and, at the Second Congress in London in 1936, a draft Code was presented and placed under the aegis of the International Committee for Bacteriological Nomenclature [later, the International Committee on Systematic Bacteriology (ICSB), and now, the ICSP]. Buchanan condensed the provisions for nomenclature into a few broad principles that are still valid today.

ICSP is a committee under the Bacteriology and Applied Microbiology Division of the International Union of Microbiological Societies (IUMS). In May 2019 an extensive revision of the statutes of the ICSP has been approved.



Minutes of the International Committee on Systematics of Prokaryotes online discussion on the proposed use of gene sequences as type for naming of prokaryotes (Click on link) 


Announcement of van Niel Prize

The van Niel International Prize for Studies in Bacterial Systematics 2020 has been awarded to Dr Tanja Woyke from The DOE Joint Genome Institute, Berkeley, USA.  The van Niel International Prize, was established in 1986 by Professor V. B. D. Skerman of the University of Queensland, to honour the contribution of scholarship in the field of microbiology by Professor Cornelis Bernardus van Niel.

The ICSP is pleased to announce the appointment of the following Life Members:

Professor Jean Euzéby (Ecole Nationale Vétérinaire, Toulouse, France) in recognition of his outstanding service in establishing and maintaining (1997-2013) the List of Prokaryotic names with Standing in Nomenclature and other contributions (see

Professor Karl-Heinz Schleifer (TUM Emeritus of Excellence, Technische Universität München, Germany) in recognition of his research and scholarly contributions to prokaryotic systematics (see

Discussion on proposed changes to the code 

Proposal to address the way the Cyanobacteria should be treated under the International Code of Nomenclature of Prokaryotes. (Click Here)

Proposal to include the rank of phylum in the International Code of Nomenclature of Prokaryotes. (Click Here)