| Episode # |
Original
Air Date |
Titles |
| |
| Season 1 |
| |
| 1. | 1-1 | 30 Apr 73 | The Slaves of Jedikiah, Part 1 |
| 2. | 1-2 | 07 May 73 | The Slaves of Jedikiah, Part 2 |
| 3. | 1-3 | 14 May 73 | The Slaves of Jedikiah, Part 3 |
| 4. | 1-4 | 28 May 73 | The Slaves of Jedikiah, Part 4 |
| 5. | 1-5 | 04 Jun 73 | The Slaves of Jedikiah, Part 5 |
| 6. | 1-6 | 11 Jun 73 | The Medusa Strain, Part 1 |
| 7. | 1-7 | 18 Jun 73 | The Medusa Strain, Part 2 |
| 8. | 1-8 | 25 Jun 73 | The Medusa Strain, Part 3 |
| 9. | 1-9 | 02 Jul 73 | The Medusa Strain, Part 4 |
| 10. | 1-10 | 09 Jul 73 | The Vanishing Earth, Part 1 |
| 11. | 1-11 | 16 Jul 73 | The Vanishing Earth, Part 2 |
| 12. | 1-12 | 23 Jul 73 | The Vanishing Earth, Part 3 |
| 13. | 1-13 | 30 Jul 73 | The Vanishing Earth, Part 4 |
| |
| Season 2 |
| |
| 14. | 2-1 | 04 Feb 74 | The Blue and the Green, Part 1: An Apple for the Teacher |
| 15. | 2-2 | 11 Feb 74 | The Blue and the Green, Part 2: The Changing Picture |
| 16. | 2-3 | 18 Feb 74 | The Blue and the Green, Part 3: The Trojan Horse |
| 17. | 2-4 | 25 Feb 74 | The Blue and the Green, Part 4: Cuckoo In The Nest |
| 18. | 2-5 | 04 Mar 74 | The Blue and the Green, Part 5: The Swarming Season |
| 19. | 2-6 | 11 Mar 74 | A Rift in Time, Part 1: Vase of Mystery |
| 20. | 2-7 | 18 Mar 74 | A Rift in Time, Part 2: Turn of the Thumb |
| 21. | 2-8 | 25 Mar 74 | A Rift in Time, Part 3: From Little Acorns |
| 22. | 2-9 | 01 Apr 74 | A Rift in Time, Part 4: Rise of the Roman Empire |
| 23. | 2-10 | 08 Apr 74 | The Doomsday Men, Part 1: Dressed to Kill |
| 24. | 2-11 | 15 Apr 74 | The Doomsday Men, Part 2: The Burning Sword |
| 25. | 2-12 | 29 Apr 74 | The Doomsday Men, Part 3: Run Rabbit Run |
| 26. | 2-13 | 06 May 74 | The Doomsday Men, Part 4: The Shuttlecock |
| |
| Season 3 |
| |
| 27. | 3-1 | 26 Feb 75 | Secret Weapon, Part 1: Found and Lost |
| 28. | 3-2 | 05 Mar 75 | Secret Weapon, Part 2: Not Quite a Sleeping Beauty |
| 29. | 3-3 | 12 Mar 75 | Secret Weapon, Part 3: Whose Side Are You On Professor |
| 30. | 3-4 | 19 Mar 74 | Secret Weapon, Part 4: A Present From Russia |
| 31. | 3-5 | 26 Mar 75 | Worlds Away, Part 1: Secret of the Pyramid |
| 32. | 3-6 | 02 Apr 75 | Worlds Away, Part 2: Hound of the Night |
| 33. | 3-7 | 09 Apr 75 | Worlds Away, Part 3: More for the Burning |
| 34. | 3-8 | 16 Apr 75 | A Man for Emily, Part 1: The Fastest Gun |
| 35. | 3-9 | 23 Apr 75 | A Man for Emily, Part 2: Here We Go Round the Doozlum |
| 36. | 3-10 | 30 Apr 75 | A Man for Emily, Part 3: Shotgun Wedding |
| 37. | 3-11 | 07 May 75 | The Revenge of Jedikiah, Part 1: Curse of the Mummy's Tomb |
| 38. | 3-12 | 14 May 75 | The Revenge of Jedikiah, Part 2: Last Chance |
| 39. | 3-13 | 21 May 75 | The Revenge of Jedikiah, Part 3: Farewell Performance |
| |
| Season 4 |
| |
| 40. | 4-1 | 21 Oct 75 | One Law, Part 1: One Law for the Poor |
| 41. | 4-2 | 28 Oct 75 | One Law, Part 2: Another for the Rich |
| 42. | 4-3 | 04 Nov 75 | One Law, Part 3: Which Prohibits Them Equally from Stealing Bread |
| 43. | 4-4 | 07 Jan 76 | Into the Unknown, Part 1: The Visitor |
| 44. | 4-5 | 07 Jan 76 | Into the Unknown, Part 2: The Father Ship |
| 45. | 4-6 | 14 Jan 76 | Into the Unknown, Part 3: The Tunnel |
| 46. | 4-7 | 21 Jan 76 | Into the Unknown, Part 4: The Circle |
| |
| Season 5 |
| |
| 47. | 5-1 | 28 Feb 77 | The Dirtiest Business Part 1: A Spy is Born |
| 48. | 5-2 | 07 Mar 77 | The Dirtiest Business Part 2: A Spy Dies... |
| 49. | 5-3 | 14 Mar 77 | A Much Needed Holiday, Part 1: Spilled Porridge |
| 50. | 5-4 | 21 Mar 77 | A Much Needed Holiday, Part 2: Just Desserts |
| 51. | 5-5 | 28 Mar 77 | The Heart of Sogguth, Part 1: Beat the Drum |
| 52. | 5-6 | 03 Apr 77 | The Heart of Sogguth, Part 2: Devil in Disguise |
| |
| Season 6 |
| |
| 53. | 6-1 | 15 May 78 | The Lost Gods, Part 1: Flight of Fancy |
| 54. | 6-2 | 22 May 78 | The Lost Gods, Part 2: Life before Death |
| 55. | 6-3 | 05 Jun 78 | Hitler's Last Secret, Part 1: Men Like Rats |
| 56. | 6-4 | 12 Jun 78 | Hitler's Last Secret, Part 2: Seeds of Destruction |
| 57. | 6-5 | 19 Jun 78 | The Thargon Menace, Part 1: Unexpected Guests |
| 58. | 6-6 | 26 Jun 78 | The Thargon Menace, Part 2: Playing with Fire |
| |
| Season 7 |
| |
| 59. | 7-1 | 09 Oct 78 | Castle of Fear, Part 1: Ghosts and Monsters |
| 60. | 7-2 | 09 Oct 78 | Castle of Fear, Part 2: Fighting Spirit |
| 61. | 7-3 | 23 Oct 78 | Achilles Heel, Part 1: A Room at the Inn |
| 62. | 7-4 | 23 Oct 78 | Achilles Heel, Part 2: Everything to Lose |
| 63. | 7-5 | 06 Nov 78 | The Living Skins, Part 1: A Harmless Fashion |
| 64. | 7-6 | 13 Nov 78 | The Living Skins, Part 2: Cold War |
| |
| Season 8 |
| |
| 65. | 8-1 | 29 Jan 79 | War of the Empires, Part 1: Close Encounter |
| 66. | 8-2 | 05 Feb 79 | War of the Empires, Part 2: Contact! |
| 67. | 8-3 | 12 Feb 79 | War of the Empires, Part 3: Standing Alone |
| 68. | 8-4 | 19 Feb 79 | War of the Empires, Part 4: All in the Mind |
| |
