The people of East Timor are voting in only its second presidential election as a free country.
The presidency is largely a ceremonial role but its profile has been boosted by incumbent Jose Ramos-Horta, a Nobel laureate who for decades has been the international face of East Timor.
Twelve candidates are running, but the race is expected to be a three-way contest between Mr Ramos-Horta, the Fretilin party's Francisco "Lu Olo" Guterres and former armed forces chief Taur Matan Ruak.
In May, East Timor will celebrate 10 years as an independent nation, which came after three years of UN administration.
The following month, voters will choose a new government in a general election.
East Timor was ruled with an iron fist by Indonesia for 24 years.
Last year the UN officially handed security responsibilities back to East Timor police, although around 1,200 UN forces remain in the country.
They will be withdrawn at the end of the year.
East Timor's own security forces will officially safeguard the elections but UN forces are ready to step in if needed, Ameerah Haq.
In Dili on Friday, United Nations Police (UNPOL) escorted local police as they distributed sealed boxes of ballot papers to polling stations around the capital, set up inside schools and other public places.
The voting age is 17, and more than 620,000 Timorese are eligible to vote at 850 polling stations nationwide.
Candidates must achieve more than 50% of the vote for an outright win, otherwise a run-off will be held in two weeks.
Formal results from Saturday's polling are not expected until early next week.
International observers and representatives from Australia, the European Union and Portuguese-speaking nations are monitoring the polls.