Steven Soderbergh is quoted saying that if the audience does not enjoy the first 10 minutes of the film then they might as well leave.

George Clooney said that Steven Soderbergh was originally considering another actor for the lead so Clooney wrote him a letter asking to be considered as he thought a letter would be "less personal" if Soderbergh wanted to turn him down. Clooney said, "thank God the other actor turned it down." The other actor was Daniel Day-Lewis.

Was originally given an R rating by the MPAA primarily due to a pair of shots of George Clooney's nude rear end. Steven Soderbergh appealed the decision, citing that similar content (and worse) had appeared on network television. Soderbergh won the appeal and the movie was granted a PG-13 rating.

Gordon uses a device that emits Higgs bosons. This is an elementary subatomic particle whose existence was predicted in 1964 by Peter Higgs and five other physicists. The particle wasn't actually observed until 2012, and in 2013 Mr. Higgs and one of his colleagues were awarded the Nobel prize for their theoretical work.

Soderbergh cast Jeremy Davies in the film after seeing a tape Davies made of himself playing Charles Manson. Davies was preparing to play Manson in an independent film. The tape was passed around within the film industry and became a popular bootleg. Davies eventually played Manson in Helter Skelter (2004).