Erdogan had 55% of the vote, compared to 39% garnered by main opposition leader Kemal Kilicdaroglu, Anadolu Agency reported.
Faik Oztrak, a spokesman for Kilicdaroglu’s center-left party, cautioned the early returns were preliminary and said the “picture is extremely positive” for the opposition.
Erdogan has ruled Turkey as prime minister or president since 2003. Pre-election polling suggested he faced the toughest reelection battle of his two decades leading the NATO member country, which has grappled with economic turmoil and the erosion of democratic checks-and-balances in recent years.
Polls closed in the late afternoon after nine hours of voting in the national election that could grant Erdogan, 69, another five-year term or see him unseated by Kilicdaroglu, who campaigned on a promise to return Turkey to a more democratic path.
If no candidate receives more than 50% of the vote, the winner will be determined in a May 28 run-off.
Voters also elected lawmakers to fill Turkey’s 600-seat parliament, which lost much of its legislative power under Erdogan’s executive presidency.
Pre-election polls gave a slight lead to Kilicdaroglu, 74, who was the candidate of a six-party opposition alliance. He leads the center-left, pro-secular Republican People’s Party, or CHP.
More than 64 million people, including 3.4 million overseas voters, were eligible to vote in the elections.
Turkey is wracked by a steep cost-of-living crisis that critics blame on the government’s mishandling of the economy.
The latest official statistics showed inflation at about 44%, down from around 86%, though independent experts believe costs continue to rise at a much higher rate.
Turkey is also reeling from the effects of a powerful earthquake that caused devastation in 11 southern provinces in February, killing more than 50,000 people in unsafe buildings. Erdogan’s government has been criticized for its delayed and stunted response to the disaster, as well as a lax implementation of building codes that exacerbated the casualties and misery.