The European country chooses between conservative historian Karol Nawrocki and pro-EU Warsaw mayor Rafal Trzaskowski.
Poles are voting in a decisive presidential run-off that could have a major impact on the nation’s future role in the European Union.
Polling began at 7am local time (05:00 GMT), with pro-EU Warsaw Mayor Rafal Trzaskowski from the centre-right Civic Platform of the governing Civic Coalition facing off against conservative historian Karol Nawrocki, who is backed by the right-wing Law and Justice (PiS) party.
The run-off follows a tightly contested first round on May 18, in which Trzaskowski won just more than 31 percent, and Nawrocki won nearly 30 percent, eliminating 11 other candidates.
The winner will succeed incumbent Andrzej Duda, the outgoing nationalist conservative president who was also backed by PiS and blamed for holding up justice reforms by using his veto against Prime Minister Donald Tusk’s centrist government.
The campaign has highlighted stark ideological divides, with the outcome expected to determine whether Poland continues along a nationalist path or pivots more decisively towards liberal democratic norms.
Trzaskowski, the 53-year-old son of a famous jazz musician, has promised to restore judicial independence, ease abortion restrictions and promote constructive ties with European partners.
Nawrocki, a 42-year-old former boxer, who is favoured by United States President Donald Trump, has positioned himself as a defender of traditional Polish values, and is sceptical of the EU.
Amid rising security fears over Russia’s war on Ukraine, both the candidates support aid to Kyiv, though Nawrocki opposes NATO membership for neighbouring Ukraine, while Trzaskowski supports it.
The two candidates have taken a similarly hardline approach to immigration, both using anti-Ukrainian rhetoric, building on growing resentment among Poles who see themselves as competing for strained social services with 1.55 million Ukrainian war refugees and migrants.
While Trzaskowski has proposed that only working Ukrainians should have access to the country’s child benefit, Nawrocki has gone further, saying he would also be against Ukraine joining NATO or even the EU.
Polls close at 9pm (19:00 GMT) when an exit poll is expected. Final results are likely to be announced on Monday.