Security chief Colonel Maurizio Mezzavilla said the bomb was similar to the ones that exploded on Thursday at the Chilean and Swiss embassies. An anarchist group with reported ties to Greek anarchists claimed responsibility for those blasts.
Greek foreign ministry spokesman Gregoris Delavekouras said from Athens that no one was harmed in the latest incident, in part because heightened security measures had already been put in place.
"The embassy was evacuated and the staff assembled some distance away from the building, so that everyone could be accounted for," he said.
"There were already heightened security measures at the Greek and other embassies, so the procedure that had to be followed was clear. The matter is now in the hands of the Italian police."
Police and firefighters massed around the building in the residential Parioli neighbourhood while the Greek Embassy staff lingered outside.
Ambassador Michalis Kambanis said the package, addressed to the embassy, was discovered at about 10.30am.
There have been several other reports of suspicious packages in recent days that turned out to be false alarms. Police responded to suspicious packages at the embassies of Venezuela, Monaco and Denmark yesterday, but all were false alarms.
"We don't take any chances in this situation," Danish foreign ministry spokesman Klavs A Holm said.
He said the embassy had received a parcel that staffers considered suspect. The embassy briefly evacuated its staff and called Italian authorities, who checked the parcel to find out it was a bottle of red wine.