Following weeks of scandal that have shaken Berlusconi's struggling centre-right government, trial was set on Tuesday to start in a criminal court in Milan on 6 April, according to a statement from the office of the city's chief judge, Christina Di Censo.
Berlusconi is not obliged to appear in person before the panel of three judges on that day, nor is there any legal obstacle to his continuing to hold office throughout any trial proceedings, which could take years before coming to any conviction.
Throughout several other legal cases, the 74-year-old premier has kept the loyalty of lieutenants in his own party, which he set up after making his fortune in business. There has been no open push from his own allies for him to stand down.
"We did not expect anything different," Piero Longo, one of Berlusconi's lawyers who sits in parliament for the ruling PDL party, told reporters after the decision was announced.
Yet the decision is perhaps the most serious political blow so far to Berlusconi, who has faced mounting public criticism as he tries to shore up a precarious majority in parliament.
A survey this week in the left-leaning La Repubblica newspaper showed that almost 50% of Italians believe the accusations against him are true, although as many believe that even if he is guilty, he will not be punished.
"He should go before the judges to defend himself like anyone else who doesn't have anything to hide and spare the country the spectacle before the world of a prime minister on trial for juvenile prostitution and abuse of office," said Dario Franceschini, a senior member of the opposition Democratic Party.
The Italian media has been dominated for weeks by the alleged prostitution affair, which turns on the case of a teenaged Moroccan nightclub dancer named Karima el Mahroug, whose stage name 'Ruby' has become a household term in Italy.
Prosecutors say they have ample evidence that Berlusconi paid el Mahroug for sex when she was under 18 - an offence in Italy - and also telephoned a police station to pressure officers to release her after she was held on theft allegations.
The charges carry a maximum sentence of three years for underage prostitution and 12 years for abuse of office.
She denies having sex with Berlusconi but admits receiving at least 7,000 euros ($9,500) after attending a party at the premier's luxurious private residence at Arcore near Milan.
Berlusconi has denied doing anything illegal in the case and says he has been targeted by politically motivated judges backed by the left who are determined to bring him down.
He says he has never paid for sex and says that when he telephoned the Milan police station it was because he believed el Mahroug to be the granddaughter of Egyptian President Hosni Mubarak and he wanted to avoid a diplomatic incident.
"I believe there is very precise and significant evidence to show that there was no abuse of office offence and no offence regarding sexual acts with a minor, and incidentally it seems very much open to debate whether this girl was a minor at all," said Maurizio Paniz, a lawyer and senior PDL deputy.
On Tuesday, Berlusconi pulled out of a news conference that was scheduled to discuss Tunisian refugees arriving in Sicily.
The constitutional court last month removed the automatic immunity from trial that Berlusconi had previously enjoyed. The prime minister is also due to face trial in three unrelated embezzlement and fraud trials in the coming weeks.
But Tuesday's decision may be only one step in a lengthy legal battle, of which many have marked Berlusconi's career.
His lawyers argue the case should be heard by a special tribunal for ministers. They have 30 days to appeal the decision to skip a preliminary hearing and go straight to trial.
The prime minister's legal problems have added a complicating factor to a political situation that was already tangled by a split in the PDL last year.
The government survived a no-confidence motion in parliament in December by a small margin. Since then, however, Berlusconi has gradually built up support by winning over deputies from smaller centrist parties and splinter formations.
There has been widespread speculation that Italy will have to hold early elections, possibly in the coming months, although Berlusconi said on Monday he was confident he had enough support in parliament to see out his full term to 2013.
On Sunday, hundreds of thousands of women across Italy demonstrated against the prime minister and the opposition has called on Berlusconi to resign and either give way to another centre-right leader or seek early elections.
Rocco Buttiglione, a member of the centrist UDC party, said the political situation had become "intolerable" and Berlusconi had become a problem for the whole country:
"Berlusconi has become a symbol of national division."
(EurActiv with Reuters.)