Former Presidents Sharif Sheikh Ahmed and Hassan Sheikh Mohamud are the frontrunners among 35 candidates.
Somali parliamentarians met in a heavily fortified airport hangar on Sunday to vote for a new president as the country battles ongoing threats of violence and a major food crisis.
In a crowded field of 35 aspirants, former Presidents Sharif Sheikh Ahmed and Hassan Sheikh Mohamud were the frontrunners, according to analysts, even though their rule failed to stem corruption or a war by armed groups.
The United Nations-backed vote was delayed by more than a year because of squabbling in government but must be held this month to ensure a $400m International Monetary Fund programme.
It takes place during the Horn of Africa nation’s worst drought in four decades and against a depressingly familiar background of violence from attacks by al-Shabab, in-fighting among security forces, and clan rivalries.
On Wednesday, a suicide bombing claimed by al-Shabab wounded seven people during political rallies near the hangar in the coastal capital Mogadishu. On Friday, fighters from an armed group battled government forces in Galmudug state.
There was a curfew across Mogadishu on Sunday, with streets quiet and shops closed.
Though just holding the vote was a success of sorts, many in the country of 15 million people were sceptical of real progress. Leading candidates were old faces recycled from the past who had done little to help them, and such votes were traditionally dominated by bribery, they complained.
Incumbent President Mohamed Abdullahi Mohamed, nicknamed “Farmaajo” for his reputed love of Italian Formaggio cheese, looked unlikely to be re-elected after losing support in last month’s parliamentary vote.
Voting can only begin once two-thirds of the members of both houses of parliament are present, with the process expected to take several hours and stretch late into the night.
Four candidates dropped out of the race on Saturday and more are expected to do so during multiple rounds of voting, narrowing the options until a winner is chosen.
The victor must secure a minimum of 184 votes.
Somalia has not held a one-person, one-vote election in 50 years.
Instead, polls follow a complex indirect model, whereby state legislatures and clan delegates pick lawmakers for the national parliament, who in turn choose the president.