Vice President Joseph Boakai of the ruling Unity Party (UP) is one of the contenders along with former global football star George Weah who is heading up the main opposition Coalition for Democratic Change (CDC). The NEC hasn't yet declared how numerous 2.2 million registered voters took part in the polls. Aside from presidential elections, 73 members of the House of Representatives will also be chosen.
In Liberia, a candidate needs more than 50% of the votes for outright victory in an election, with experts forecasting it is likely to go to a second round.
Weah, a former Fifa World Footballer of the Year, has failed in two previous attempts to become the country's president.
Vice-President Joseph Boakai and footballer George Weah are seen as the frontrunners to succeed the Nobel Peace Prize victor Ellen Johnson Sirleaf who led the country's recovery from Ebola and civil war. In one case, hundreds of people with registration cards spent the day demanding to vote in Bong County after poll workers there said their names were not on voter rolls.
The first official results are expected within 48 hours after polls close.
"No matter the outcome of this election, it will result in a transfer of power from one democratically elected government to another for the first time in the lives of many Liberians", it said in a statement.
Global observers say the polls went smoothly despite late start to voting in some counties.
The election turnout was impressive, especially among younger generations, said Christopher Fomunyoh of the USA -funded National Democratic Institute, which was monitoring the elections. He said Liberia's youth demonstrated "a commitment to be involved in the electoral and governmental process of their country".