Updated: June 29, 2024

Although it retains a following, the science-fiction community often points to Lost in Space as an example of early television's perceived poor record at producing science-fiction. The series' deliberate fantasy elements, a trademark of Irwin Allen productions, were perhaps overlooked as it drew comparisons it to its supposed rival, Star Trek. However, Lost in Space was a mild ratings success, unlike Star Trek, which received very poor ratings during its original network TV run. The more "cerebral" Star Trek never averaged higher than 52nd in the ratings during its three seasons, while Lost in Space finished season one with a rating of 32nd, season two in 35th place, and the third and final season in 33rd place.

Star Trek creator Gene Roddenberry insisted that the two shows could not be compared. He was more of a philosopher, while understanding that Irwin Allen was a storyteller. When asked about Lost in Space, Roddenberry acknowledged: "That show accomplishes what it sets out to do. Star Trek is not the same thing".

While Lost in Space was still reasonably successful, the show was unexpectedly canceled in 1968 after 83 episodes. The final primetime episode to be broadcast across the USA was a cast and crew favorite, a repeat from the second season, "A Visit to Hades", on September 11, 1968.

Lost in Space is remembered, at least, from often-repeated lines of the Robot, such as "Warning! Warning!", "That does not compute" and "Danger, Will Robinson!". Smith's frequent put-downs of the Robot are also still popular ( "You bubble-headed booby!" ) as are his trademark lines: "Oh, the pain... the pain!" and "Never fear, Smith is here!". One of Jonathan Harris's last roles was providing the voice of the illusionist praying mantis "Manny" in Disney's "A Bug's Life", where Harris used "Oh, the pain... the pain!" near the end of the film.

Lost in Space was the favorite show of the son of President John F. Kennedy, John F. Kennedy, Jr. while growing up in the 1960s.