Mr Berlusconi is likely to appeal and will remain free in the meantime.
He is presently appealing against another conviction and faces two more verdicts in the coming weeks.
One of the rulings expected later this month is about tax fraud, and the other trial concerns allegations the he paid for sex with an underage prostitute.
Transcript
In October last year, Mr Berlusconi was convicted in another tax fraud case and sentenced to a year in jail.
That conviction is currently subject to an appeal.
Prosecutors brought the wiretap case after a transcript of a phone conversation intercepted by the authorities was published in the newspaper Il Giornale, owned by Mr Berlusconi’s brother Paolo.
The conversation took place between the head of insurer Unipol and Piero Fassino, who was the leader of the biggest centre-left party and Mr Berlusconi’s biggest political rival at the time.
Unipol was trying to take over BNL bank in 2005. Magistrates had ordered the wiretap as part of an investigation into inappropriate interference in the takeover.
The publication of the transcript in a national newspaper broke secrecy rules, and Mr Berlusconi was accused of obtaining the transcript from the wiretap company used by magistrates.
In numerous trials over the years, Mr Berlusconi has been accused of charges including accounting fraud, perjury, bribery, corruption, having unlawful sex with a minor, and fraud over the sale of film rights.
Mr Berlusconi says he is the target of a vendetta by politically biased prosecutors. He has denied all the accusations against him and has either been acquitted or let off under statutes of limitations.
Source: BBC