The 2009 index, which measures perceived levels of public sector corruption, determined that Somalia, plagued by decades of war and a crumbling government infrastructure, is the world's most corrupt country.
At the top of the 10-point scale used by the group was New Zealand at 9.4, followed by Denmark (9.3), Singapore and Sweden (9.2) and Switzerland (9.0).
Somalia's 1.1 rating was slightly worse than Afghanistan (1.3), Myanmar (1.4), and Sudan and Iraq (both 1.5).
The United States ranked 19th with a 7.5 rating.
"When essential institutions are weak or non-existent, corruption spirals out of control and the plundering of public resources feeds insecurity and impunity," Transparency International said in a statement from its Berlin headquarters.