The court will rule on whether to uphold a tax fraud conviction against the former premier and confirm the one-year prison sentence and a five-year ban
from public office, which would effectively end his 20-year political career.
The 76-year-old is unlikely to be jailed because of his age, but his banishment from parliament would be a blow to the centre-right. It could also unsettle Prime Minister Enrico Letta's centre-left and right coalition, already riven with bickering.
The trial, which began seven years ago, concerns Berlusconi's Mediaset business empire. It revolves around prices of film distribution rights bought by the company that were artificially inflated in order to avoid taxes.
The tax scam helped the fraudsters create secret overseas accounts and reduce profits to pay fewer taxes in Italy.
Prosecutor Laura Bertole insisted in her summing up in March that the buck stopped with Berlusconi, "who has always been at the head of the chain of command."
The former cruise-ship crooner, who denies the charges, says he was too busy with his political career to deal with issues such as film rights.
Berlusconi's position as a senator offers him some protection, for even if the court upholds the guilty verdict against him, it will be for the senators to vote on whether to deprive him of his seat in the upper house.
It is not clear how long the Rome court will take to examine the case.
While a ruling could come as early as Tuesday, the hearings could also last several days. The judges may even postpone their decision to later in the year.
Both Berlusconi and Letta have insisted that the Mediaset ruling will not have an effect on the government.
Some political analysts however have warned that the mogul's loyalists are plotting to pull the plug and force a fresh election if he is definitively found guilty.
But others say the former premier knows the risks of such a move are too high; among other things, a withdrawal of his centre-right People of Freedom (PDL) party from government could open the way to an alliance between the left and Italy's Five Star protest movement.
The right would also need time before the next general election to establish its identity, after two decades under the showman's helmsmanship.
Whatever the court's decision, it is unlikely to signal the end of Berlusconi.
Many analysts dismissed him as a political force after he was ousted from power at the end of 2011, but he staged an impressive comeback for the elections in February, almost stealing victory from a shocked left, which was later forced to share power.
Even if he were ousted from parliament, he may very well bid to stay on as a figurehead for the right.
Prime minister briefly in 1994, then from 2001 to 2006 and again from 2008 to 2011, Berlusconi's battles with the law have marked his public life but he has repeatedly benefited from criminal statutes of limitation.
The self-made billionaire has faced charges including corruption, tax fraud, false accounting and illegally financing political parties, but while some initial judgements have gone against him, he has never been definitively convicted.
In June, Berlusconi was sentenced to seven years in jail for paying for sex with an underage prostitute and abusing his power to hide the liaison, but the sentence was suspended to allow for a lengthy appeals process.