George Clooney was 42 years old at the time of filming the scene in which the other actors guess his age.
Vincent Cassel did not need a stuntman for the laser dance. He is an expert in capoeira, a Brazilian dance-like martial art, and performed the entire dance himself. The lasers, however, were added in post.
While on production in Rome, Brad Pitt and George Clooney were not allowed back into the hotel because the doorman thought they were vagrants after the actors were caught in a rain storm while jogging.
The Night Fox's mansion is on the shores of Lake Como in Italy. The name of the city overlooking Lake Como is Bellagio. The city and the lake were the inspiration for the design of the Bellagio casino in Las Vegas, site of the heist in Ocean's Eleven (2001).
Matt Damon requested, just prior to the beginning of production, that the script be revised so that his character would have a smaller role in the story. Damon had just finished shooting the action-packed The Bourne Supremacy (2004), and claimed that he was too exhausted to play a character that had such a major role in the movie. Director Steven Soderbergh denied Damon's request, claiming that he felt Damon's character was integral to the plot, and that giving Damon less screen time would diminish his character's impact on the plot.