Ahead of Sunday’s run-off vote, opposition rival Kemal Kilicdaroglu has courted nationalist votes by vowing to expel millions of Syrian refugees.
The president accused him of hate speech – and said a Kilicdaroglu victory would be a win for terrorists.
The opposition candidate trailed in the first round by 2.5 million votes.
The president is favourite, but his rival believes the margin could still be bridged – either by the 2.8 million supporters of an ultranationalist candidate who came third or by the eight million voters who did not turn out in the first round.
Before their campaigns drew to a close on Saturday evening, Mr Erdogan marked the anniversary of a 1960 coup with a visit to the mausoleum of an executed prime minister.
It was a reminder to voters that in 2016 he had faced down an attempted coup, and that the government would be safe in his hands.
His rival met a group of women hit by Turkey’s economic crisis, promising that, if elected, he would live modestly, rather than in a presidential palace.