| "Zero Sum" | |
|---|---|
| Series The X-Files Season 4, Episode 21 | |
| File:X-Files 4x21 001.jpg | |
| Air date | April 27th, 1997 |
| Writers | Glen Morgan; James Wong |
| Director | Kim Manners |
| Producers | Chris Carter; Rob Bowman; Joseph Patrick Finn; Vince Gilligan; R.W. Goodwin; Howard Gordon; Ken Horton; Kim Manners; Glen Morgan; Lori Jo Nemhauser; Paul Rabwin; Frank Spotnitz; James Wong |
| Starring | David Duchovny; Gillian Anderson |
| Episode guide | |
| Previous "Small Potatoes" |
Next "Elegy" |
"Zero Sum" is the twenty-first episode of season four of the paranormal television series The X-Files and the 75th episode of the series overall. It was directed by Kim Manners and written by Glen Morgan and James Wong. It first aired on the Fox Network on Friday, April 27th, 1997.