Tabare Vazquez has taken office as Uruguay's first leftist president.
Thousands of flag-waving supporters crowded outside the Congress building in Montevideo, where Mr. Vazquez was sworn in Tuesday for a five-year term.
The 65-year-old president is a cancer specialist and former mayor of Montevideo. He came to power on pledges to help the country's poor, and is also expected to restore diplomatic relations with Cuba.
Cuban leader Fidel Castro canceled his plans to attend the inauguration for health reasons.
Among those attending the inauguration were the presidents of Bolivia, Chile, Paraguay and Peru as well as Spain's Crown Prince Felipe. The U.S. delegation was led by Labor Secretary Elaine Chao.
Some information for this report provided by AP.