Slovenia uses the euro.
The eurozone , officially called the euro area , is a monetary union of 19 of the 28 European Union ( EU ) member states which have adopted the euro as their common currency and sole legal tender . Slovenia . It has been severely hurt by the Eurozone crisis , started in the late 2000s . In 2004 , it entered NATO and the European Union ; in 2007 became the first formerly communist country to join the Eurozone ; and in 2010 joined the OECD , a global association of high-income developed countries .