American television drama that began airing on the Columbia Broadcasting System (now CBS Corporation) in 2000. Since then it has become one of the most popular television programs in the United States.

CSI: Crime Scene Investigation chronicles the work of a virtuoso team of Las Vegas-based criminologists who solve murders using forensic science and their own preternatural investigative skills. Long led by night-shift supervisor Gil Grissom (played by William Petersen, previously best known for his film work, especially in To Live and Die in L.A. 【1985】), the team is routinely called upon to process and analyze evidence at crime scenes. Using procedures that mirror those of their real-life counterparts, the team works both in the field and in the lab, in conjunction with other law enforcement officers. Each member of the team brings a different personality and skill to the proceedings, and their clashes and relationships contribute to the narrative tension. Inevitably, their findings spur a conventional murder-mystery plot. But rather than following leads and conducting interviews, the CSI team solves crimes using scientific methods and analysis of evidence. The show is known for its graphic depictions of gruesome crimes, acts of violence, and autopsies. Dramatic graphics and special effects guide the viewer through the show's science. Critics of the series have pointed to the implausibility of some of the team's techniques and findings and have questioned the portrayal of crime scene investigation. Despite such criticisms, the show has consistently been in the top 10 of the Nielson ratings and has been nominated for numerous Emmy Awards.

The series has become a franchise for CBS, with direct spin-offs including CSI: Miami and CSI: New York (which began in 2002 and 2004, respectively), along with ties to the shows Cold Case (which first aired in 2003) and Without a Trace (first broadcast in 2002).