Ahmadinejad's plane touched down at Rome's Ciampino airport shortly after 9:00 am, the airport news agency reported.
The Iranian leader said he would be holding talks with "world leaders" on the sidelines of the Food and Agriculture Organization (FAO) summit on food security, but did not specify which ones.
Italian activists, leftist politicians and Jewish groups have protested against Ahmadinejad's presence at the summit, saying it was a disgrace to host someone who has repeatedly predicted Israel's disappearance.
"Iran, as an influential nation in the economy and agriculture, has clear solutions, programmes and suggestions for the fair production and distribution of food supply in the world," Ahmadinejad said before leaving Tehran, according to Iran's the official IRNA news agency.
"Iran can play a decisive role in today's world management," he added. Ahmadinejad has visited UN headquarters in New York for the UN General Assembly on three occasions, but visits by him to any Western country are extremely rare.
