"I am on trial, but on trial with me is the freedom of expression of many Dutch citizens," Wilders, who is likely to be a kingmaker when the next government is formed, told the Amsterdam district court.
Wilders told the court he was being persecuted for "stating my opinion in the context of public debate".
And he addd, "I can assure you, I will continue proclaiming it."
Wilders, 47, risks up to a year in jail or a 7,600-euro fine for calling Islam "fascist" and likening the Koran to Hitler's Mein Kampf.
He is charged with five counts of giving religious offence to Muslims and inciting hatred and discrimination against Muslims and people of non-Western immigrant origin, particularly Moroccans.
He told judge Jan Moors his intention was "to defend freedom of expression and leave a better Netherlands for the next generation".
Wilders told the court that apart from this opening statement, he would rely on his right to remain silent and would not answer any questions. This was on the advice of his advocate, Bram Moszkowicz.
"I have said everything I wanted to say and will not take back a single word," Wilders said.