The X-Files aired 9 original seasons from 1993 to 2002. The science-fiction series premiered on Fox on September 10, 1993, and its original run ended with the finale "The Truth" on May 19, 2002.
Those nine seasons contained 202 episodes and followed FBI agents Fox Mulder and Dana Scully as they investigated paranormal cases and government conspiracies. The series began as a cult hit but became one of Fox's defining programs and a major influence on later mystery and science-fiction television.
The wording "original seasons" matters because The X-Files later returned for two revival seasons. Season 10 aired in 2016 with six episodes, while season 11 aired in 2018 with ten episodes. Counting those revivals produces 11 seasons in total, but they are not part of the 1993–2002 original run.
Another common mix-up is confusing seasons with episodes: the original series had nine seasons but 202 episodes. The franchise also includes two theatrical films, released in 1998 and 2008.