Season 1
| 1 | Pilot | 2004-07-11 |
| 2 | The New and Improved Carl Morrissey | 2004-07-18 |
| 3 | Becoming | 2004-07-25 |
| 4 | Trial by Fire | 2004-08-01 |
| 5 | White Light | 2004-08-08 |
Season 2
| 1 | Wake-Up Call | 2005-06-05 |
| 2 | Voices Carry | 2005-06-12 |
| 3 | Weight of the World | 2005-06-19 |
| 4 | Suffer the Children | 2005-06-26 |
| 5 | As Fate Would Have It | 2005-07-10 |
| 6 | Life Interrupted | 2005-07-17 |
| 7 | Carrier | 2005-07-24 |
| 8 | Rebirth | 2005-07-31 |
| 9 | Hidden | 2005-08-07 |
| 10 | Lockdown | 2005-08-14 |
| 11 | The Fifth Page | 2005-08-21 |
| 12 | Mommy's Bosses | 2005-08-28 |
| 13 | Mommy's Bosses | 2005-08-28 |
Season 3
| 0 | Unlocking the Secrets | 2006-06-03 |
| 1 | The New World | 2006-06-11 |
| 2 | Being Tom Baldwin | 2006-06-18 |
| 3 | Gone: Part 1 | 2006-06-25 |
| 4 | Gone: Part 2 | 2006-07-02 |
| 5 | Graduation Day | 2006-07-09 |
| 6 | The Home Front | 2006-07-16 |
| 7 | Blink | 2006-07-23 |
| 8 | The Ballad of Kevin and Tess | 2006-07-30 |
| 9 | The Starzl Mutation | 2006-08-06 |
| 10 | The Gospel According to Collier | 2006-08-13 |
| 11 | Terrible Swift Sword | 2006-08-20 |
| 12 | Fifty-Fifty | 2006-08-27 |
| 13 | Fifty-Fifty | 2006-08-27 |
Season 4
| 1 | The Wrath of Graham | 2007-06-17 |
| 2 | Fear Itself | 2007-06-24 |
| 3 | Audrey Parker's Come and Gone | 2007-07-01 |
| 4 | The Truth and Nothing But the Truth | 2007-07-08 |
| 5 | Try the Pie | 2007-07-15 |
| 6 | The Marked | 2007-07-22 |
| 7 | Till We Have Built Jerusalem | 2007-07-29 |
| 8 | No Exit | 2007-08-05 |
| 9 | Daddy's Little Girl | 2007-08-12 |
| 10 | One of Us | 2007-08-19 |
| 11 | Ghost in the Machine | 2007-08-26 |
| 12 | Tiny Machines | 2007-09-09 |
| 13 | The Great Leap Forward | 2007-09-16 |