"It's the first phone call in the world using the new technology over a real network," said H3G's chief executive officer, Vincenzo Novari.
The call was made by Italy's communications minister, Maurizio Gasparri, who used his mobile videophone to ring Guido Gentili, the editor of Italian business daily Il Sole 24 Ore.
"This is a significant leap into the future, given that with this technology you can see images and navigate on the Internet," Gasparri told reporters. "Obviously, like all novelties, UMTS will need a bit of time before it becomes a mass technology."
However, calls made via (3G) technology based on UMTS or its equivalent outside of Europe - W-CDMA - may not be as much of a novelty as Gasparri indicated.
Wind has recently been testing calls on a 3G network in Italy and NTT DoCoMo started commercial 3G services in Japan based on W-CDMA last year.
H3G, which is marketing its service under the brand name 3, is investing €5bn (£3.2bn) in the Italian service and expects to cover at least 80 cities by the end of the year, according to Novari.
"We're playing the role of the hare. Without us, the third generation of mobile phones would have taken a few more years to become a reality," he said.
The company will begin distributing its first videophones to customers on an experimental basis next month and commercial service is scheduled to begin in January.