Information on established syndromic surveillance systems was collected from peer-reviewed articles (found in MEDLINE, Scopus and Google Scholar), proceedings from all ISDS Conferences and other conferences and searches through reference lists of papers. In addition, web pages of international health organizations, surveillance networks and Ministries of Health were explored. Identified syndromic surveillance systems were categorized by country, resource level and surveillance methodology, among other features. Eight systems were selected and examined in detail to extract transferable information.