Of a field of seven presidential candidates, incumbent 78-year-old President Peter Mutharika faces stiff competition from his vice-president, Saulos Chilima, 46, and from Lazarus Chakwera, 64, leader of the main opposition, the Malawi Congress Party.
Malawi's winning candidate must get the most votes cast but is not required to receive more than 50% of the votes.
Previous president Joyce Banda dropped out of the race and is supporting Chakwera.
Of the registered voters, 54% are young people between the ages of 18 and 34. Women make up 56% of the registered voters while all the presidential candidates are male.
Malawi's army and police will provide security at the more than 5,000 polling stations across the country and polls will remain open for 12 hours until 6 p.m. local time.
Most voters interviewed said they are pleased to cast their ballots in the hotly contested presidential poll.
"We are tired with all these months of bickering and I just want to vote and be done with it," said Martha Liunda, 66, in Blantyre.
William Phiri, 32, an inmate at Chichiri prison in Blantyre said he was excited to be able to vote for a candidate of his choice even though he is in jail.
"I have two years to serve and I am voting for a future that I will find upon my release," he said.
Malawi's voting system is secure and "cannot be penetrated by hackers," said electoral commission chairwoman Jane Ansa, speaking to the press Monday evening. No communications networks will be shut down during the elections, she said.
The presidential contest is very close between the top three contenders, said Boniface Dulani, a senior lecturer in political science at Chancellor College, University of Malawi.
As in previous elections, he says voting is likely to follow regional lines where Chakwere and the Malawi Congress Party will carry the central region, Chilima the north and Mutharika the south.
"The decider will most likely be who comes second in all the regions," he said.
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