Ejection from the Senate following his conviction for tax fraud would mean Berlusconi being out of parliament for the first time since 1994, when the media and construction magnate first burst onto Italy's political scene.
His centre-right People of Freedom (PDL) party immediately announced an appeal in a bid to delay the moment the political guillotine will fall for a man who has dominated Italian affairs of state for the past two decades.
The full Senate must vote before Berlusconi can be ousted, but the 77-year-old media magnate's supporters are in the minority.
Berlusconi was given a 12-month sentence after the supreme court on August 1 turned down his final appeal in the tax fraud case, handing him his first ever definitive conviction in a long history of legal woes.
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He was also barred from holding public office for two years, which means however the Senate votes he is likely to lose his seat.
The punishment is not likely to be meted out before next year.