Prosecutors say Wilders has incited hate against Muslims, pointing to a litany of quotes and remarks he has made in recent years. In one opinion piece he wrote "I've had enough of Islam in the Netherlands; let not one more Muslim immigrate," adding "I've had enough of the Koran in the Netherlands: Forbid that fascist book."
Wilders argues he has a right to freedom of speech and that his remarks were within the bounds of the law.
"I am a suspect here because I have expressed my opinion as a representative of the people," Wilders told judges at the start of the trial.
"Formally I'm on trial here today, but with me, the freedom of expression of many, many Dutch people is also being judged," he said, referring to more than 1.4 million voters who made his party the country's third-largest in June elections.
If convicted he could face up to a year in jail, though a fine would be more likely. He could keep his seat in parliament regardless of the outcome.
The trial was adjourned until Tuesday shortly after Wilders' opening remarks, when he declined to answer any questions from the three judges, invoking his right to remain silent.
Presiding judge Jan Moors said Wilders is known for making bold statements but avoiding discussions, and added that "it appears you're doing so again".
Wilders' lawyer, Bram Moszkowicz, said the remark showed Moors is biased against Wilders and moved to have him substituted. The move delayed the trial for at least a day as a separate panel considers the request.
The move for a delay comes at delicate moment in Dutch politics when Wilders is close to seeing many of his policy goals realised.
Wilders' Freedom Party has agreed to support a new right-wing Dutch government set to take office this month, despite reservations even by some politicians about working with Wilders.
In return, his political allies have promised to carry out much of his anti-immigration agenda. They say they will turn away more asylum-seekers, and cut immigration from non-Western countries in half, notably by making it difficult for foreign spouses or children to join families that have already immigrated and become Dutch citizens.
They also plan to force new immigrants to pay for their own mandatory citizenship classes.
Immigration-related issues have dominated politics in the Netherlands and much of Europe over the past decade. Wilders has drawn comparisons with populists such as the late Jorg Haider in Austria and Jean-Marie Le Pen in France.
His stances resound deeply with Dutch voters, who have reconsidered their famous tolerance amid fears their own culture is being eroded by immigrants who don't share their values. Around 6% of the Dutch population is now Muslim.
The flamboyant, bleach-blond politician also has called for taxing clothing commonly worn by Muslims, such as headscarves - or "head rags," as he once called them - because they "pollute" the Dutch landscape.
He may be best known for the 2008 short film Fitna, which offended Muslims around the world by juxtaposing Koran verses with images of terrorism by Islamic radicals.
In a sign of the emotions at stake in Wilders' political rise, Naziism is invoked on both sides. Wilders compares the growth of Islam influences in the Netherlands to the rise of Nazi ideology, while his critics say his populist, anti-foreigner rhetoric is reminiscent of Hitler's.
A handful of anti-Wilders protesters gathered outside the court behind a banner reading "fascism rules," with a Dutch pun on Wilders' name.
Mohamed Rabbae, chairman of the moderate National Moroccan Council, said outside the court that he hoped judges would force Wilders to issue an apology for his past remarks.
"We are not for getting Mr Wilders in prison. We are for correcting him," Rabbae said.
The case has generated huge interest in the Netherlands and the opening was broadcast live on television.
The formal charges are insulting a group on the basis of its religion and inciting discrimination and/or hatred.
Convictions for discriminatory remarks are frequent in the Netherlands, but penalties are rarely greater than a small fine.
Prosecutors were initially reluctant to bring Wilders' case to court, saying his remarks appeared directed toward Islam as an ideology rather than intended to insult Muslims as a group.
But they were eventually ordered to do so by a judge.
Prosecutors won't rule out dropping some or all charges or demanding no sentence when the trial comes to its concluding phase.
A verdict is expected on November 4, though if the current panel of judges is replaced, the trial will be delayed for months.
