How many episodes will there be in series four of lost?
Originally, 16 episodes were planned for season four. Eight
episodes were written, filmed, and edited before the WGA strike.
These eight episodes have already aired in the United States. After
the strike ended, the producers of LOST announced that they would
condense the storyline they had planned into five more episodes in
season four. In total, there will be 13 episodes in season four.
The three episodes they were unable to produce this season will be
added to seasons five and six.