The Summit of the Americas, which brings together all countries in the hemisphere except Cuba, started on Friday at a hotel in Port of Spain, the capital of Trinidad and Tobago.
This will be US President Barack Obama's first major meeting with Latin American leaders and his first trip to the region since taking office in January.
Venezuelan President Hugo Chavez was the first to enter the conference hall, as part of a parade in which each leader entered the room preceded by a flag-wielding soldier dressed in white.
The global economic crisis and the situation of Cuba, which was suspended from the Organisation of American States (OAS) in 1962, were expected to be the focus of the meeting, which was formally set to discuss energy security, environmental sustainability and democratic governance.