Ecuadorians are voting Saturday on a reform package critics say could give President Rafael Correa too much power.
The referendum contains 10 questions, which range from a bullfighting ban to an increase in executive branch control on appointing judges.
The referendum also includes a measure that would set up a panel to regulate media content and hold individual journalists responsible for any violations. Some say the move is aimed at silencing dissent. Another press-related reform would bar media companies from other commercial interests.
Opposition leaders say Correa is using the referendum to increase his power.
Polls suggest the leftist president's popularity could help deliver the votes needed to pass the referendum.
President Correa has headed Ecuador since 2007. He is an ally of other leftist Latin American leaders, including Venezuelan President Hugo Chavez and Bolivia's Evo Morales.
Some information for this report was provided by AP, AFP and Reuters.