Marcello Dell-Utri, a senator in Berlusconi's Forza Italia (Go Italy) party and a former chairman of the prime minister's advertising firm Publitalia, was sentenced on Saturday to nine years in prison.
The verdict came less than 24 hours after Berlusconi escaped conviction in a major corruption trial in Italy's financial capital Milan, and gave fresh ammunition to opponents of the centre-right government.
Dell'Utri had been accused of acting as a link between the Mob and Italy's business and political elite.
Longer sentenced desired
Prosecutors had demanded an 11-year jail term, saying Dell'Utri had frequent contacts with the Mafia when he worked for the Berlusconi family's holding company Fininvest from 1974 to 1994.
Berlusconi narrowly escaped
conviction in his trial on Friday
Dell'Utri vowed to appeal against the decision, which would also bar him from public office. At a news conference, he bitterly remarked that "justice is not of this Earth" and tried to distance his conviction from Berlusconi, who travels to the United States next week to meet President George Bush.
"Berlusconi is perhaps my greatest friend, the foremost person to be pained by this ruling. But to say that this conviction is also a moral conviction for Berlusconi is a bit excessive," he said.
His lawyer, Enzo Trantino, described the ruling as just the "first round in a long battle."
Dell'Utri helped create Forza Italia and acted as Berlusconi's campaign manager in the 1994 election which first catapulted the media mogul to power.
Berlusconi, who named Dell'Utri to Forza Italia's executive board last week, reportedly told party members: "I wouldn't put one hand in the fire for him, I would put both."
On Saturday, however, he was silent.
"Yesterday, the prime minister was saved by the skin of his teeth, and today his confidant Marcello Dell'Utri is convicted. This political class is not worthy of governing the country"
Antonio di Pietro,
"No. I'm not making any comment," Berlusconi told reporters in Venice.
The court took 13 days to reach a verdict - a record for the Palermo anti-Mafia tribunals.
Berlusconi escaped conviction in his nearly five-year-old trial on Friday after a court invoked a statute of limitations, meaning time had run out to sentence him.
Statute of limitation
The ruling implied that the 68-year-old prime minister was guilty of one count of authorising a $434,404 bribe to a Rome judge in 1991 but could not be sentenced because of the time limit. The court then acquitted Berlusconi of a second charge of bribing the judiciary.
"Yesterday, the prime minister was saved by the skin of his teeth, and today his confidant Marcello Dell'Utri is convicted," said opposition politician Antonio di Pietro, a former star
"This political class is not worthy of governing the country."
Dell'Utri was found guilty of extortion in a separate trial in April and sentenced to two years in jail, charges he has always denied. He is appealing against that verdict, too.
"I am ready to continue to fight, more than before .... I am only resigned at the fact that it (the verdict) happened, like thunder in the sky - I can't stop it," he said.