
The two-hour series finale was aired on September 27, 2015. Seasons eleven, twelve, thirteen, and fourteen set a new standard of 22 episodes per season, but the fifteenth season received a reduced order of 18 episodes.

Season nine had 24 episodes, and season ten returned to the series standard of 23 episodes. During seasons six and seven, the episode count was 24, whereas season eight had 17 episodes due to the WGA strike. Seasons two, three, and four also had 23 episodes each, while season five had 25 episodes, including a two-part season finale directed by Quentin Tarantino. The first season consisted of 23 episodes, including a two-part pilot episode written by series creator Anthony E.

Since then, fifteen seasons have been broadcast. Episodes of American television series CSI: Crime Scene InvestigationĬSI: Crime Scene Investigation premiered on October 6, 2000.
