In July 2004, co-stars George Eads and Jorja Fox were fired (by direct order of CBS head Leslie Moonves) for breach of contract. CBS said that they were using delay tactics (refusing to show up for shooting) to force a pay raise at the beginning of the fifth season. They were soon rehired, but without a raise. They both denied that there was any contract dispute - Eads says he just overslept on the first day of production, and Fox said she didn't know about the letter of intent she reportedly failed to sign.
Though not requested to do so by the producers, Marg Helgenberger attended actual autopsies over the course of the series for personal research purposes. The most 'memorable' aspect of the experience was the stench, according to Helgenberger's account on BBC's Breakfast (3 November 2011).
While the majority of the techniques and technologies used in the show are accurate and true to reality, the writers and crew readily admit that they "time cheat". Tests that take seconds in the show often take days or even weeks in real life.
Grissom, et. al. use the Nikon F5 fitted with a multi-control back for photographing crime scene elements. As of the 5th season, this is no longer true. Most have different cameras: e.g. Warrick uses either a Nikon D70 or Nikon D100.
In response to a TV Guide interview that revealed Jorja Fox may leave CSI, fans began a "Dollar for Sense" campaign and sent over 2,000 dollar bills to CBS. The campaign also included three banner flyovers of CBS in Los Angeles, and flowers for her every day for a week.
You often hear the characters referring to a four-nineteen (4-19,4/19, etc.) or sometimes a 4-45. These are the Las Vegas Metro 400 Event codes. The often-used 419 stands for "deceased person", while the less-used 445 is "explosive device threat".