The ousted president of Catalonia hailed Catalans as “irrepressible”, vowing to return to power.
In a statement on Twitter, he said: “Today we will demonstrate the strength of an irrepressible people.
“Let the spirit of October 1 guide us always.”
October 1, the date of Catalonia’s declaration of independence, marked a turning point in the dramatic sequence of events, causing Spain to dissolve the regional government and impose direct rule.
In the face of legal threats, including a possible 30-year prison sentence for separatist leaders, the Catalan parliament passed independence with a significant majority.
Mr Puigdemont is fighting the regional election from self-imposed exile in Belgium, where he is avoiding arrest for “rebellion” against the Spanish constitution.
Many other Catalan leaders are in prison in Madrid for their part in declaring the region’s independence.
However his vow to demonstrate Catalans are “irrepressible” is a signal his fight for an independent state will continue.
Spanish prime minister Mariano Rajoy, on the other hand, is hopeful high turnout can halt the march towards Catalan independence.
Mr Rajoy forced the vote when he fired Catalonia’s government and dissolved its parliament following the region’s declaration of independence in October.
Huge swathes of pro-union voters will have to turn out at the polls if Mr Rajoy’s risky move is going to pay off.
Mr Rajoy has called on Catalans to turn out “massively” to vote in an election he described as “crucial for Catalonia, for Spain and for the ensemble of Europe”.
The likely outcome is a hung parliament and there will be many weeks of wrangling to form a new regional government in Catalonia.