With about almost all ballots counted from Sunday’s first round, incumbent Laurent Gbagbo won 38% and opposition leader Alassane Ouattara 32%, the election commission said.
The run-off is due later this month.
The poll is intended to fully reunify the country, after years of rebel control in the north.
The election, due since 2005, had been postponed six times.
Some feared violence could break out after the announcement of the final results. There had been increasing tension with the delay in announcing the outcome of the election in the world’s biggest cocoa producer.
The head of the country’s army called for calm on state television before the first results were released late on Tuesday.
Mr Ouattara, a former IMF economist, is popular in the mainly Muslim north, where many people have complained that they face discrimination.
He was excluded from previous polls amid accusations that his parents were of foreign origin.
Former President Henri Konan Bedie, the third main candidate, took 25% of the vote, the Independent Election Commission (CEI) said. Turnout was about 80%.
His Ivory Coast Democratic Party (PDCI) called for a recount, accusing the electoral commission of publishing false results.
The PDCI governed Ivory Coast for 39 years since independence until Mr Bedie was ousted in a coup in 1999.
Ivory Coast used to be seen as a haven of political stability and prosperity in West Africa.
Northern rebels took up arms in 2002, dividing the country for five years, until a power-sharing deal was signed in 2007.
The ex-rebel New Forces leader Guillaume Soro became prime minister but – aged 38 – he is too young to stand in the election.
Source: BBC