How many episodes were in season 4 of Lost?

13.

There were 13 episodes in season 4 of the hit ABC TV series ‘˜Lost’™. The season premiered on regular American TV on January 31, 2008. The 2-hour season finale was aired on May 29, 2008. The season was affected by the writers’™ strike of the American Writers Guild in November 2007 to February 2008, resulting in a month-long hiatus between the 8^th and 9^th episode for the season.