The Enrico Ievoli, owned by the Naples company Marnavi, was captured near the coast of Oman, the Italian news agency ANSA reported.
The pirates were aboard the ship but crew members, including 18 Italians, had not been harmed, the ship's commander, Agostino Musumeci, said by telephone, Marnavi Chief Executive Domenico Ievoli said.
Last week, another Italian oil tanker, the Savina Caylyn, owned by Fratelli D'Amato of Naples, was freed after being hijacked by Somali pirates in February.
Italy's foreign ministry denied pirates claim a ransom had been paid.
And in October, an Italian ship hijacked off the coast of Somalia was freed after an operation by British special forces.
Pirates are believed to have taken in $80 million in ransom money last year, ANSA said, but governments agreed this year not to pay ransom.
Last week, the European Union anti-piracy mission said Somali pirates were holding 200 hostages for ransom after pirating their ships in the Indian Ocean.