Background: Since 2000, a periodic count has been done of active members in Cochrane Review Groups (CRGs), subdivided by the country in which these people are based. Objectives: To assess international activity within Cochrane Review Groups of The Cochrane Collaboration. Methods: Using Issue 1, 2008 of The Cochrane Library, data were taken from the section headed ‘‘Editorial information’’ in each CRG’s module (repeating the exercise from previous years). Data were extracted by one of the authors (CA) and can be analyzed by role within the CRG and the country of residence. If a country had not been allocated to a person, he or she was not included. If a person was listed more than once, he or she was counted each time. Results: Among 51 CRGs, 17,637 contributors were identified from 103 countries. This is an increase from 15,740 (100 countries) in 2007; 14,925 (97) in 2006; 13,047 (97) in 2005; 11,517 (91) in 2004; 9281 (83) in 2003; 7727 (78) in 2002; and 5436 contributors (64) in 2000. In 2008, 10,698 (61%) contributors were listed as authors, compared with 9445 (60%) in 2007, 8823 (59%) in 2006, 7543 (58%) in 2005, 6695 (58%) in 2004, 5159 (55%) in 2003, 4250 (55%) in 2002, and 2840 (52%) in 2000. The number of contributors based in countries classified by The World Bank as low, lower-middle, or upper-middle income economies continues to increase and is now 13% (2252 contributors) of the total. Conclusions: The number of contributors and international coverage continues to increase. The relative contribution of different countries is variable, but there is a yearly increase in the number of contributors from low, lower-middle and upper-middle income economy countries. This increase is proportionally greater than for highincome economy countries. The spreadsheet is available at http:// www.cochrane.org/docs/contributorsbycountry.htm. As it is increasingly common for the contact details of contributors to The Cochrane Collaboration to be stored in Archie, the Collaboration’s contact database, we expect to use this, rather than The Cochrane Library, for future counts.