"This is a very special day for my family as well as for auto racing," Andretti, 66, said at the Commendatore della Repubblica ceremony. "And it is an honor I am particularly proud of. I am Italian, my blood is Italian. The fact I have the passport of another country doesn't change my feelings."
Andretti was born in Montona d'Istria, Italy, an area of the Istrian peninsula that is now Motovun, Croatia. He emigrated to the United States in 1955.
He is the only driver to have won the Indianapolis 500, the Dayton 500 stock car race, the Champ car title and the Formula 1 championship with Lotus in 1978, the Italian news agency ANSA noted.
Andretti said seeing Italian driver Alberto Ascari in the 1950s at Monza inspired him to become a racecar driver.
Exploding whale video goes viral on Internet
Jordana Brewster on Paul Walker: 'He was an enormous presence in my life'