Sebastian Pinera has promised to continue the centre-left's social policies
Conservative billionaire Sebastian Pinera has won Chile's presidential run-off, ending two decades of centre-left rule.
Christian Democrat Eduardo Frei conceded defeat after results from 60% of polling stations showed Mr Pinera with 52% of the vote to Mr Frei's 48%.
Mr Pinera promised a tough law-and-order programme and vowed to use his business know-how to boost the economy.
Outgoing President Michelle Bachelet was barred by law from standing again.
Mr Pinera has promised to continue her highly popular social policies.
He will be Chile's first democratically elected conservative leader for more than half a century.
Mr Pinera's victory ends the long run in office of the Concertacion - a coalition of left-wing and centre parties that had run Chile since the end of military rule under Gen Augusto Pinochet in 1990.
Mr Pinera won 44% of the vote in last month's first round, well ahead of Mr Frei, the governing Christian Democrat candidate.
Mr Pinera, 60, made his fortune introducing credit cards to Chile.
He now owns a television channel, a stake in Chile's most successful football club and has millions of dollars in investments.
He has promised to increase investment, fight crime and create one million jobs, the BBC's Candace Piette reports from the capital, Santiago.
He has also promised to cut taxes for small businesses and make government more efficient.
"Better times are coming for Chile. There is a great new phase on the way," Mr Pinera said on Sunday.
"After 20 years I think a change will be good for Chile. It's like opening the windows of your home to let fresh air come in."
It was the second time Mr Pinera had run for the presidency at the head of a centre-right coalition.
Eduardo Frei had been seeking a second term as president
In 2006, he lost to Socialist Ms Bachelet. Under the constitution she could not stand for re-election in 2010.
She will leave office in March with a high approval rating as a result of policies to tackle poverty and use Chile's all-important copper exports to offset the effects of the global economic crisis.
Mr Frei, 67, had promised a continuation and deepening of many of her policies.
He had been seeking his second term as president after an absence of 10 years.
Conceding defeat, he said Chile was "much better than the country we received in 1990".
"We will be guardians of liberty and of all our social victories," he said.