| Title | Original Air Date | Stardate | Writer | Director |
|---|---|---|---|---|
| Original Pilot | ||||
| The Cage | N/A | Unknown | Gene Roddenberry | Robert Butler |
| Season 1 | ||||
| The Man Trap | 9/8/66 | 1513.1 | George Clayton Johnson | Marc Daniels |
| Charlie X | 9/15/66 | 1533.6 | Gene Roddenberry | Lawrence Dobkin |
| Where No Man Has Gone Before | 9/22/66 | 1312.4 | Samuel A. Peeples | James Goldstone |
| The Naked Time | 9/29/66 | 1704.2 | John D. T. Black | Marc Daniels |
| The Enemy Within | 10/6/66 | 1672.1 | Richard Matheson | Leo Penn |
| Mudd's Women | 10/13/66 | 1329.1 | Gene Roddenberry | Harvery Hart |
| What Are Little Girls Made Of? | 10/20/66 | 2712.4 | Robert Bloch | James Goldstone |
| Miri | 10/27/66 | 2713.5 | Adrian Spies | Vincent McEveety |
| Dagger of the Mind | 11/3/66 | 2715.1 | S. Bar-David | Vincent McEveety |
| The Corbomite Maneuver | 11/10/66 | 1512.2 | Jerry Sohl | Joseph Goldstone |
| The Menagerie, Part I | 11/17/66 | 3012.4 | Gene Roddenberry | Marc Daniels |
| The Menagerie, Part II | 11/24/66 | 3013.1 | Gene Roddenberry | Marc Daniels |
| The Conscience of the King | 12/8/66 | 2817.6 | Barry Trivers | Gerd Osward |
| Balance of Terror | 12/15/66 | 1709 | Paul Schneider | Vincent McEveety |
| Shore Leave | 12/29/66 | 3025.3 | Theodore Sturgeon | Robert Sparr |
| The Galileo Seven | 1/5/67 | 2821.5 | Oliver Crawford | Robert Gist |
| The Squire of Gothos | 1/12/67 | 2124.5 | Paul Schneider | Don McDougall |
| Arena | 1/19/67 | 3045.6 | Fredic Brown | Joseph Pevney |
| Tomorrow is Yesterday | 1/26/67 | 3113.2 | D. C. Fontana | Michael O'Herlihy |
| Court Martial | 2/2/67 | 2947.3 | Don M. Mankiewicz | Marc Daniels |
| The Return of the Archons | 2/9/67 | 3156.2 | Gene Roddenberry | Joseph Pevney |
| Space Seed | 2/16/67 | 3141.9 | Carey Wilber | Marc Daniels |
| A Taste of Armageddon | 2/23/67 | 3192.1 | Robert Hamner | Joseph Pevney |
| This Side of Paradise | 3/2/67 | 3417.3 | Nathan Butler and D. C. Fontana | Ralph Senensky |
| The Devil in the Dark | 3/9/67 | 3196.1 | Gene L. Coon | Joseph Pevney |
| Errand of Mercy | 3/23/67 | 3198.4 | Gene L. Coon | John Newland |
| The Alternative Factor | 3/30/67 | 3087.6 | Don Ingalls | Joseph Pevney |
| The City on the Edge of Forever | 4/6/67 | 3134.0 | Harlan Ellison | Joseph Pevney |
| Operation Annihilate! | 4/13/67 | 3287.2 | Steven W. Carabastos | Herschel Daugherty |
| Season 2 | ||||
| Amok Time | 9/15/67 | 3372.7 | Theodore Sturgeom | Joseph Pevney |
| Who Mourns for Adonais? | 9/22/67 | 3468.1 | Gilbert Ralston | Marc Daniels |
| The Changeling | 9/29/67 | 3451.9 | John Meredyth Lucas | Marc Daniels |
| Mirror, Mirror | 10/6/67 | Unknown | Jerome Bixby | Marc Daniels |
| The Apple | 10/13/67 | 3715.0 | Max Ehrlich | Joseph Pevney |
| The Doomsday Machine | 10/20/67 | 4202.9 | Norman Spinrad | Marc Daniels |
| Catspaw | 10/27/67 | 3018.2 | Robert Bloch | Joseph Pevney |
| I, Mudd | 11/3/67 | 4513.3 | Stephen Kandel | Marc Daniels |
| Metamorphosis | 11/10/67 | Unknown | Gene L. Coon | Ralph Senensky |
| Journey to Babel | 11/17/67 | 3842.3 | D. C. Fontana | Joseph Pevney |
| Friday's Child | 12/1/67 | 3497.2 | D. C. Fontana | Joesph Pevney |
| The Deadly Years | 12/8/67 | 3478.2 | David P. Harmon | Joesph Pevney |
| Obsession | 12/15/67 | 3619.2 | Art Wallace | Ralph Senensky |
| Wolf in the Fold | 12/22/67 | 3614.9 | Robert Bloch | Joseph Pevney |
| The Trouble With Tribbles | 12/29/67 | 4523.3 | David Gerrold | Joseph Pevney |
| The Gamesters of Triskelion | 1/5/68 | 3211.7 | Margaret Armen | Gene Nelson |
| A Piece of the Action | 1/12/68 | 4598.0 | David P. Harmon | James Komack |
| The Immunity Syndrome | 1/19/68 | 4307.1 | Robert Sabaroff | Joseph Pevney |
| A Private Little War | 2/2/68 | 4211.4 | Jud Crucis | Marc Daniels |
| Return to Tomorrow | 2/9/68 | 4768.3 | John Kingsbridge | Ralph Senensky |
| Patterns of Force | 2/16/68 | 2534.0 | John Meredyth | Vincent McEveety |
| By Any Other Name | 2/23/68 | 4657.5 | Jerome Bixby | Marc Daniels |
| The Omega Glory | 3/1/68 | Unknown | Gene Roddenberry | Vincent McEveety |
| The Ultimate Computer | 3/8/68 | 4729.4 | Laurence N. Wolfe | John Meredyth Lucas |
| Bread and Circuses | 3/15/68 | 4040.7 | Gene Roddenberry and Gene L. Coon | Ralph Senensky |
| Assignment: Earth | 3/29/68 | Unknown | Gene Roddenberry and Are Wallace | Marc Daniels |
| Season 3 | ||||
| Spock's Brain | 9/20/68 | 5431.4 | Lee Cronin | Marc Daniels |
| The Enterprise Incident | 9/27/68 | 5027.3 | D. C. Fontana | John Meredyth Lucas |
| The Paradise Syndrome | 10/4/68 | 4842.6 | Margaret Armen | John Meredyth Lucas |
| And the Children Shall Lead | 10/11/68 | 5027.3 | Edward J. Lakso | Marvin Chomsky |
| Is There In Truth No Beauty? | 10/18/68 | 5630.7 | Jean Lisette Aroeste | Ralph Senensky |
| Spectre of the Gun | 10/25/68 | 4385.3 | Lee Cronin | Vincent McEveety |
| Day of the Dove | 11/1/68 | Unknown | Jerome Bixby | Marvin Chomsky |
| For the World Is Hollow and I Have Touched the Sky | 11/8/68 | 5476.3 | Rik Collaerts | Tony Leader |
| The Tholian Web | 11/15/68 | 5693.2 | Judy Burns and Chet Richards | Herb Wallerstein |
| Plato's Stepchildren | 11/22/68 | 5784.0 | Meyer Dolinsky | David Alexander |
| Wink of an Eye | 11/29/68 | 5710.5 | Lee Cronin | Jud Taylor |
| The Empath | 12/6/68 | 5121.0 | Joyce Muskat | John Erman |
| Elaan of Troyius | 12/20/68 | 4372.5 | John Meredyth Lucas | John Meredyth Lucas |
| Whom Gods Destroy | 1/3/69 | 5718.3 | Lee Erwin and Jerry Sohl | Herb Wallerstein |
| Let That Be Your Last Battlefield | 1/10/69 | 5730.2 | Lee Cronin | Jud Taylor |
| The Mark of Gideon | 1/17/69 | 5423.4 | George F. Slavin and Stanley Adams |
Jud Taylor |
| That Which Survives | 1/24/69 | Unknown | Michael Richards | Herb Wallerstein |
| The Lights of Zetar | 1/31/69 | 5725.3 | Jeremy Tarcher and Shari Lewis | Herb Kenwith |
| Requiem For Methuselah | 2/14/69 | 5843.7 | Jerome Bixby | Murray Golden |
| The Way to Eden | 2/21/69 | 5832.3 | Michael Richards and Arthur Heinemann | David Alexander |
| The Cloud Minders | 2/28/69 | 5818.4 | David Gerrold and Oliver Crawford | Jud Taylor |
| The Savage Curtain | 3/7/69 | 5906.4 | Gene Roddenberry | Herschel Daugherty |
| All Our Yesterdays | 3/14/69 | 5943.7 | Jean Lisette Areosete | Marvin Chomsky |
| Turnabout Intruder | 6/3/69 | 5928.5 | Gene Roddenberry | Herb Wallerstein |