The country’s Constitutional Court annulled the November election won by NATO critic Calin Georgescu.
Romanians are casting ballots in the presidential election months after a previous vote held in November was annulled over allegations of Russian interference.
Polls opened at 7am local time (04:00 GMT) and will close at 9pm (18:00 GMT), with exit polls expected shortly afterwards. Far-right politician George Simion is expected to win the first round, according to opinion polls.
The Constitutional Court cancelled the last vote won by NATO critic Calin Georgescu, who has been barred from the rerun.
Georgescu was excluded from the rerun following a huge TikTok campaign and claims of Russian interference, sparking sometimes violent protests. He has effectively been replaced by Simion, one of 11 presidential hopefuls vying for the largely ceremonial but influential foreign policy post in Sunday’s first round.
Simion opposes military aid to neighbouring Ukraine, is critical of European Union leadership and says he is aligned with the United States President Donald Trump’s “Make America Great Again” movement.
He is currently polling at about 30 percent, a comfortable lead but well short of the 50 percent he needs to avoid a run-off on May 18.
Simion’s main rivals are two centrists, former Senator Crin Antonescu, 65, backed by the three parties in the current pro-Western government, and Bucharest Mayor Nicusor Dan, 55, running as an independent on an anticorruption platform.
Both are pro-EU, pro-NATO and back Ukraine. Victor Ponta, a former leftist prime minister who has turned conservative nationalist, is ranked fourth but could prove a dark horse.
“George Simion equals Calin Georgescu, he gets my vote,” Aurelia, 66, a pensioner who declined to give her last name, told the Reuters news agency and said she felt “humiliated” by the cancellation of November’s first round.
“Everything is lacking here. My children are not here: Did they leave to work abroad because things were so good here?”
Pensioner Eugenia Niculescu, 65, who lives in Bucharest and has struggled to pay for her medication and other bills amid soaring inflation, told the AFP news agency: “We want a capable person who knows how to speak up for the Romanian people in the EU.”
Romania’s president is limited to two five-year terms, and has a semi-executive role that includes commanding the armed forces and chairing the security council that decides on military aid.
The president represents Romania at EU and NATO summits, can veto important EU votes and appoints the prime minister, chief judges, prosecutors and secret service heads.