Poles will vote in a closely contested race that pits the centrist, pro-European ruling party's candidate, Warsaw Mayor Rafal Trzaskowski against nationalist challenger Karol Nawrocki who draws inspiration from U.S. President Donald Trump and is backed by the main opposition Law and Justice party.
The rivals are neck-and-neck in opinion polls.
The runoff setting reflects the duopoly of centrists and nationalists that has dominated Polish politics for two decades.
The election takes place against a backdrop of rising anti-establishment sentiment in Poland, with the far-right achieving their strongest ever showing.
In Poland, the job of president is largely ceremonial, but comes with crucial veto power.
A Trzaskowski victory would give the government a major boost, while a Nawrocki win would reinforce its difficult cohabitation with the president.
Click on the player icon above for an audio report by Michał Owczarek.