President Evo Morales, whose leftist economic policies have made him broadly popular with Bolivia's poor but angered business leaders, is expected to win re-election on Sunday, allowing him to expand state control over the economy.
A victory by Morales would solidify his dominance over Bolivian politics and further weaken a divided conservative opposition tied to the country's business elite. Opinion polls show Morales, an ally of Venezuela's socialist President Hugo Chavez, winning easily with more than 50 percent support. To avoid a run-off vote, he needs to garner more than 40 percent and hold a 10-point lead over his closet rival.
His Movement Toward Socialism party is expected to win control of Congress.
Morales, Bolivia's first indigenous president, nationalised the energy industry in his first term, which generated a windfall for state coffers that he has used to boost social spending.
The cash payments to school children, new mothers and the elderly have added to his popularity among Bolivia's disenfranchised Indian majority that celebrated his defeat of the country's long-ruling traditional parties four years ago.
"Evo is helping us; he gave me a pension," said Tomas Gutierrez Chura, an 83-year-old retired bus driver who voted in the town of Huatajata on the shores of Lake Titicaca.
A former llama herder and coca leaf farmer raised in extreme poverty, Morales faces two conservative rivals: Manfred Reyes Villa, a former governor and army captain who has about 20 percent support in opinion polls, and wealthy cement magnate Samuel Doria Medina, who stands at about 10 percent.
Morales has cast himself as the only candidate able to bring prosperity to the poor, and many Bolivians living in rural areas identify strongly with his humble origins. Morales vows to extend the hand of the state deeper into Bolivia's gas- and mineral-rich economy to redistribute wealth in South America's poorest country. The Bolivian economy is expected to grow 2.8 percent this year, the highest rate in Latin America, according to the International Monetary Fund.