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 a few seconds in the show, often take several days or even weeks in real-life.
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 (November 3, 2011).
A fallout between George Eads and one of the female writers of the show, prompted the absence of Eads for five consecutive episodes, without explanation for the character, in season fourteen, including the milestone three hundredth episode.
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.
In real-life, the Las Vegas Metropolitan Police Department (LVMPD) Crime Scene Investigators (CSIs) are not detectives, and are called Crime Scene Analysts (CSAs). Most present day applicants are surprised to discover that the CSAs do not perform most of the tasks depicted on the series. For example, they do not interview suspects, they do not write or execute search warrants, and they do not make arrests. In real-life, they are directed around the scenes by the detectives and supervisors, not the other way around. Detectives are commissioned police officers (sworn personnel). CSAs are civilian personnel, not sworn, and do not have the same arrest powers as police officers. However, they are very skilled technicians, and are a component of the police response to crime.
You often hear the characters referring to a four-nineteen, 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".
Real-life prosecutors have complained about something known as the "CSI Effect", where juries have unrealistic expectations about forensic science, either expecting copious amounts of forensic evidence, in even routine cases, or expecting an unrealistic level of accuracy and specificity from the tests presented.
At the conclusion of each case, the culprits almost always confess their guilt to investigators, that would most assuredly not be the people interviewing them, this helps to wrap up the case in a Scooby Doo-like manner for the general viewing public.
The trivia items below may give away important plot points.
The oft-mentioned Tangiers Casino that was built and owned by Sam Braun in the series is completely fictional. There is no such casino in Las Vegas or anywhere else in the world. The name is often used by television shows and movies to bypass any potential copyright issues, or if a local casino doesn't give permission to use their name or likeness.
William Petersen took a small leave of absence to perform on a Providence, Rhode Island stage during season seven, and the character of Michael Kepler (played by Liev Schreiber) was created to be a temporary replacement.
In response to a TV Guide interview that revealed Jorja Fox may leave CSI, fans began a "Dollar for Sense" campaign, and sent over two thousand 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.
Grissom and company use the Nikon F5 fitted with a multi-control back for photographing crime scene elements. As of the fifth season, this is no longer true. Most have different cameras: for example, Warrick uses either a Nikon D70 or Nikon D100.