This is the country's first national election after the end of 25 year civil war with the LTTE in May 2009.
68,000 police personnel including 25 Army battalions have been deployed in the coutry to prevent any disruption in the election process in which Muslims and Tamil are seen as the deciding voters.
Basking on his success in putting an end to the LTTE activities in the country, Rajapaksa decided to call for election, two years ahead of schedule.
Rajpaksa faces stiff competition from his opponent Army Commander General Sarath Fonseka, who is also credited with the government's victory against the LTTE.
Earlier on Monday, Jan 25 Rajapaksa assured a free and fair election.
"All campaigning for this election is now concluded. It is a duty and responsibility of all citizens of our country who value democracy to extend their fullest co-operation to the Commissioner of Elections to conduct a free and fair election," said Rajapaksa in a statement.
Voting will end at 4.00pm in the evening. The polling result is expected to be put by Wednesday, Jan 27.