(UK) University of East Anglia
Number Theory research.

Number Theory Centres
Listed in the Number Theory Web.

(UK) University of Oxford
Number Theory Group. Members, publications, meetings.

(USA) University of Georgia
Number Theory and Arithmetic Geometry Group. Members, seminars.

(UK) University of Glasgow
Number Theory and Combinatorics. Staff, research interests.

(UK) King's College, University of London
Number Theory Group. Staff, meetings, preprints.

(UK) Nottingham University
Number Theory and Arithmetic Geometry research group. Research interests, members, visitors, meetings.

(UK) University of Durham
Geometry and Arithmetic Group. Members, meetings, preprints.

(Europe) Arithmetic Algebraic Geometry
A European network of 12 working groups from 6 countries.

(USA) University of Illinois at Urbana-Champaign
Number Theory faculty, visitors, meetings, courses, events.

(USA) Brown University
Number Theory/Arithmetic Geometry Seminar. Members, meetings.

(USA) University of Texas
Number Theory Group. Members, meetings, software.

(Canada) Queen's University, Kingston
Algebra and Number Theory Group. Members, research interests.

(Israel) Ben Gurion University of the Negev
Number Theory and Algebraic Geometry Research Group. Members, research interest, seminars.

(USA) Texas A and M University
Combinatorics/Number Theory Directory.

(USA) University of California, Los Angeles
Number Theory Group. Members, events, resources.

(Europe) GTEM: Galois Theory and Explicit Methods in Arithmetic
Research training network coordinated in Paris, uniting twelve teams from July 2000 until June 2004.

(USA) University of South Carolina
Number Theory Group. Members, research interests, courses, links.

(South Africa) The John Knopfmacher Centre for Applicable Analysis and Number Theory, University of the Witwatersrand
Members, research interests, preprints, meetings.

(USA) University of California, Santa Cruz
Number Theory Seminar meetings.

(USA) Boston University
Algebra and Number Theory Research Group. Members, research interests, seminars, courses.

(Russia) Steklov Institute, St. Petersburg
Laboratory of Number Theory. Research interests.

(Brazil) Universidade de Brasília
Automorphic Forms and Number Theory group. Members, research interests.

(USA) Penn State
Algebra and number theory group. Members, seminars, preprints, links.

(Austria) University of Natural Resources, Vienna
Number theory group led by Werner Georg Nowak. Members, research interests, publications, links.

(Austria) University of Vienna
Johannes Schoißengeier's number theory research group. Members, research interests, links to other Austrian number theorists.

(Finland) University of Oulu
Number theory research interests.

(USA) CUNY
Arithmetic Geometry Seminar meetings.

(Finland) University of Turku
Number Theory Group. Members, research interests.

(Canada) Simon Fraser University
Number Theory Group. Members, meetings, courses.

(Netherlands) University of Leiden
Number theory research group. Staff, events, links.

(Hungary) Eötvös University, Budapest
Department of Algebra and Number Theory. Members pages.

(Germany) Technische Universität, Berlin
Algebra and Number Theory: the KANT group. Members, software (KANT/KASH), publications.

(Netherlands) Thomas Stieltjes Institute
Number Theory courses and activities.

(Hungary) Alfréd Rényi Institute of Mathematics, Hungarian Academy of Sciences
Number Theory research group staff.

(USA) Arizona State University
Number Theory Graduate Program. Faculty, courses.

(Germany) University of Heidelberg
Algorithmic Algebra and Number Theory. Members, research, activities, software, links.

(Austria) Technical University of Graz
Algorithmic and Probabilistic Number Theory Research Group. Members, research interests.

(UK) Royal Holloway, University of London
Research areas (mainly analytic/combinatorial), members.

(UK) Loughborough University
Department of Mathematical Sciences: Number Theory group.

(USA) University of Wisconsin, Madison
Algebra, Combinatorics and Number Theory Group. Members, seminars.

(UK) University of York
Number Theory Research Group.

(Canada) McMaster University
Algebra/Number Theory Seminar. Meetings, abstracts.

(USA) University of California, Santa Barbara
Arithmetic and Geometry Seminar. Meetings.

(USA)University of Michigan
Graduate Program in Number Theory. Staff, research interests, courses, seminars.

(Sweden) Uppsala University
Mathematics III research group: quantum chaos and number theory.

(Lithuania) Vilnius University
Department of Probability Theory and Number Theory.

(Croatia) University of Zagreb
Seminar on Number Theory and Algebra. Members, seminars, links.

(Canada) CICMA, Concordia University, Montreal
Number Theory Page. Members, seminars, preprints.

(Germany) University of Siegen
Algebra and Number Theory group. Members, research interests.

(USA) Caltech
Underground Number Theory Seminar. Schedule of meetings.

(USA) Brigham Young University
Number Theory Seminar. Schedule.

(Hungary) Academy of Sciences
Department of Computer Algebra and Number Theory research group.

(UK) Cardiff University
Number Theory Group. Members, research interests, advice to research students.

(Germany) Clausthal University of Technology
Institut für Mathematik - Number Theory Research Group. People, research topics.

(USA) University of Rochester
Algebra and Number Theory Group. Members, research interests, seminar schedule.

(UK) University of Cambridge
Number Theory Seminar. Meetings.

(Canada) University of Toronto
Number Theory/Representation Theory Seminar. Schedule of meetings.

(Saudi Arabia) King Fahd University
Algebra and Number Theory Group. Members.

(Slovakia) Comenius University, Bratislava
Department of Algebra and Number Theory. Research topics, contact information.

(Japan) Okayama University
Number Theory Group. Members.

(Ukraine) Tavrical National University
Department of Algebra and Number Theory. Members, research interests, publications.

(Spain) Seminari de Teoria de Nombres de Barcelona (UPC)
Members, research topics, publications, schedules.

(USA) University of California Irvine
Number theory seminar. Meetings, study groups, links.

(Canada) University of British Columbia
Number Theory group. Members, research areas and meetings.

(Italy) University of Pisa
Number Theory Group. Research interests and members.

(China) Shandong University
Number theory research group. Members, research interests, courses, events.

(USA) Southwestern Center for Arithmetical Algebraic Geometry
Based at the University of Arizona, in collaboration with the Universities of New Mexico, Southern California, and Texas. Annual conference.

(Netherlands) CWI, Amsterdam
Computational number theory group. Members, research interests, publications.

(Poland) Polish Academy of Sciences
Department of Number Theory. Members, research interests, publications.

(Canada) McMaster University
Arithmetic Geometry Seminar. Members, meetings.

(Hungary) Lajos Kossuth University, Debrecen
Department of Algebra and Number Theory. Staff list.