Here are the alternative titles for selected episodes of Space:1999. Unless noted, all are working titles used during production.
- Breakaway: 'Zero G', 'The Void Ahead', 'Turning Point'
- Force of Life: 'Force of Evil'
- Matter of Life and Death: 'Siren Planet'
- The Last Enemy: 'The Second Sex', 'The Other Enemy'
- The Metamorph: 'The Biological Soul', 'The Biological Computer'
- One Moment of Humanity: 'One Second of Humanity'
- The AB Chrysalis: 'The Chrysalis A-B-C'
- The Seance Spectre: 'The Mutiny'
- Devil's Planet: 'Devil's Moon'
- The Immunity Syndrome[N 1]: 'The Face of Eden' (From the Original Script)
- The Dorcons: 'Return of the Dorcons', 'The Last of the Psychons' (From the Original Script)