The migrant crisis has become the key issue.
Ninety-thousand people claimed asylum in Austria last year, equivalent to about 1% of the Austrian population, and the Freedom Party has run a campaign against immigration.
The presidency is a largely ceremonial post but a Hofer victory could be the springboard for Freedom Party success in the next parliamentary elections, scheduled for 2018.
Austria is faced with a stark choice for its head of state: a Green Party professor, Alexander Van der Bellen, or Norbert Hofer of the far-right Freedom Party - a soft-spoken, charismatic gun enthusiast who won a decisive victory in the first round of voting in April.
For the first time since the Second World War, the traditional parties of the centre left and centre right were knocked out of the race.