Vienna retained the top spot in the ICCA 2009 rankings, followed by Barcelona, while Copenhagen, which hosted the UN COP15 climate conference in December, moved from 11th to 6th place.
Madrid moved into the top 20, taking joint 13th place with Budapest, while Tokyo dropped off the list after being placed joint 19th in the 2008 rankings.
ICCA UK and Ireland chair and Excel London director of conferences and events James Rees credited London's ranking improvement in part to: "the new partnership approach across the city led by Visit London working with venues, hotels, transport providers and the Mayor's office to vastly improve London's congress proposition. After Beijing, London is now in the spotlight in the lead-up to the 2012 Olympic and Paralympic Games and the city venue and hotel offer is now at its most competitive for years."
ICCA Top 20 city rankings 2009
11 Buenos Aires
18 Sao Paulo
ICCA Top 20 country rankings 2009
5 United Kingdom
15 Republic of Korea