Chavez's influence over Latin America's left-leaning governments has often rankled the United States, Venezuela's largest trading partner. Venezuela is the fourth-largest exporter of oil to the United States. Despite that tight economic relationship, the two countries are not exactly close allies: Chavez often rails against the U.S. and its allies as "imperialists."
Further complicating the U.S.-Venezuela relationship is how Chavez is allied with Iran's Mahmoud Ahmadinejad, defended former Libyan leader Moammar Gadhafi and has even offered his support for Syria's leader Bashar al-Assad.
At stake for Venezuelans is the ideological trajectory of their country.
Chavez, 58, has had more than a decade to implement his vision of 21st century socialism, a view that emphasizes use of state oil windfalls to fund social programs.
Observers say Capriles, 40, represents a moderate alternative.
He has vowed not to end the social programs that Chavez has set up, and he promises to fight corruption that has grown in the public sector.
The candidates offer two distinct paths to solve the problems that are on Venezuelans minds: decaying infrastructure, high crime rates and political polarization.
The election also drew voters from beyond the country's borders as thousands of Venezuelans living abroad lined up to cast their ballots at diplomatic offices.
In New Orleans, Louisiana, voters streamed into the Venezuelan Consulate. Many traveled by bus from Miami, where Venezuelan authorities closed a consulate in January after the United States expelled the office's top Venezuelan diplomat.
In Caracas, voters said they were happy to be casting their ballots.
"I'm really proud of the people, because everyone is cheerful about this event and I think there is a good feeling," said Jesus Betancourt, a 25-year-old student.
Standing outside the Caracas school where Chavez cast his ballot, Katherene Rivas said she hoped Venezuelans would respect the results.
"For now, everything is quiet here, and we want that after the results are announced, that people remain calm," she said.