The film received warm applause at a press screening on Saturday.
"Up in the Air" tells the story of a man, Ryan Bingham, on a mission to rack up a million frequent-flyer miles as he travels across America as a corpotate downsizer.
Vera Farmiga plays his love interest, who tests his desire to live an isolated life on the road.
The movie is director Jason Reitman's follow-up to "Juno," which won in Rome in 2007 and went on to become a best-picure nominee at the Oscars.
The Rome festival runs through Oct. 22.