Leonard Nimoy, David McCallum, Cliff Robertson, Barbara Rush and Peter Breck are the only actors to appear in both this series and Rumbo a lo desconocido (1963).
Several episodes contain plot threads that link them together. For example, the "Innobotics arc", the story of life-like androids created by the Innobotics Corporation, runs through these episodes: "Valerie 23", "Mary 25", "The Hunt", "In Our Own Image", and "Resurrection".
Sam Egan, the writer of the award-winning 100th episode Tribunal (1999), based the story of the episode on his father's experience in Auschwitz during World War II, where his first wife and their young daughter were murdered by the Nazis.
The Sci-Fi Channel (now Syfy) took over co-production for the seventh and final season in 2001 after the series was cancelled by Showtime.
When it premiered on TV2 in New Zealand, Sandkings (1995) was the first episode of the series to be given a viewer warning at the beginning of the episode for its frightening scenes. All episodes were rated AO adults only on TV2.