Presidential and parliamentary elections in Ghana have attracted a huge turnout with few reported problems, poll officials say.
President John Kufuor, stepping down after serving the maximum two terms, urged participants to accept the result peacefully and in good faith.
The race to succeed him is considered to be a tight one.
The main contenders are ex-foreign minister Nana Akufo-Addo and the opposition's John Atta Mills.
Mr Atta Mills, of the National Democratic Congress, is a candidate for the top office for a third time.
Many arrived at polling stations early, waiting for their chance to vote as the day's temperatures rose. There were delays of about an hour in some areas as voting materials arrived late, reports say.
"Voter turnout is going to be very high. I should expect a higher number than we saw in the last elections because I could see this one is very competitive," Electoral Commission Chairman Kwadwo Afari-Gyan said. Turnout in 2004 was a record 85%.
In as much as we need change, we must maintain the peace we enjoy
Polls were due to close at 1700 GMT but officials said those still queuing would be allowed to vote.
Ghana is often held up as an example of good government in Africa and the continent is said to be watching how the vote unfolds.
Mr Kufuor said he wanted to see decorum.
Mr Atta Mills, who served as vice-president under Ghana's former leader Jerry Rawlings, said he expected it would be peaceful.
"In any contest you expect a winner and a loser, and parties are likely to accept the results if indeed the conduct of the process is free, fair and transparent," he said.
The New Patriotic Party's Mr Akufo-Addo, a British-trained lawyer, said: "We have battled a long, arduous struggle to turn our nation into a democratic state, so an occasion like this, the fifth successive election that we have had in the last 20 years, is an extremely significant and important day in the evolution of our democracy and its consolidation."
There is little love lost between the two main political parties, the BBC's Will Ross says, and both are looking for victory.
At one polling station, business student Sarah Walker said she was worried about unemployment levels and had lots of friends who had "finished school and are roaming the streets". But she also hoped for a peaceful transition.
Ghanaians say they are setting an example to the rest of Africa
"In as much as we need change, we must maintain the peace we enjoy," she said. "We are very scared of what has happened in countries around us, like Liberia, Ivory Coast, Sierra Leone."
The Convention People's Party, which ushered in Ghana's independence, has picked up support from people disillusioned with the two main parties.
Its candidate, Paa Kwesi Nduom, may secure enough votes to prevent the other leading candidates from achieving a first-round victory, says our correspondent.
This election is important not just for Ghana, but also for the continent, he says.The fact that the hallmark for a successful election is that it is peaceful is seen by some as a worrying sign of just how low the bar has been set when it comes to judging democracy in Africa, says our correspondent.