What was the name of the robot on the 1960s sci-fi series Lost in Space who often said 'Danger, Will Robinson'?

Robot B-9 is the commonly used name or model identification for the robot on the 1960s sci-fi series Lost in Space, though many viewers simply know the character as The Robot. The Robot became one of the most memorable parts of Lost in Space, especially because of the warning phrase “Danger, Will Robinson,” which linked the machine closely to young Will Robinson and the dangers faced by the stranded space-traveling family.

Lost in Space premiered on CBS in 1965 and became one of the best-known examples of 1960s science fiction television. The series followed the Robinson family, who set out aboard the spacecraft Jupiter 2 on a mission to colonize a planet near Alpha Centauri. Their journey was thrown off course after sabotage by Dr. Zachary Smith, leaving the family lost far from Earth. The show mixed space adventure, family drama, comic relief, and futuristic gadgets, making it a familiar part of mid-1960s television.

The Robot was built into the show as a powerful mechanical helper, protector, and source of information. In the story, the robot was part of the Jupiter 2 mission and could perform tasks that were too dangerous, too technical, or too physically demanding for the humans. It had extendable arms, a clear dome-like head, flashing lights, a rolling base, and a voice that made it instantly recognizable. Its design gave it a machine-like appearance, but the character’s behavior often felt emotional, loyal, and surprisingly human.

The Lost in Space robot name can be a little confusing because the character was not usually addressed in the show the way a human character would be. On screen, it was often called “Robot” or “the Robot.” The designation Robot B-9 became widely used by fans, reference works, collectors, and later franchise material to identify the character more specifically. For many people, Robot B-9 is the best-known formal name, while The Robot remains the simple name remembered from the series.

The connection between The Robot and Will Robinson helped give the character its emotional center. Will, played by Billy Mumy, was the youngest Robinson child and often formed bonds with unusual or misunderstood figures, including the Robot and Dr. Smith. The Robot frequently warned Will when danger was near, which is why “Danger, Will Robinson” became so strongly associated with the series. The exact wording varied in the show, but the phrase became part of popular culture as a shorthand for an urgent warning.

The Robot’s voice was supplied by actor Dick Tufeld, whose delivery gave the machine its authority and personality. Tufeld’s voice was deep, formal, and dramatic, which made even simple warnings sound important. Bob May performed inside the robot suit, giving the character movement and physical presence. Together, the voice and performance helped turn a prop-like machine into one of the show’s standout characters.

Lost in Space also became known for the relationship between The Robot and Dr. Zachary Smith, played by Jonathan Harris. Smith often insulted the Robot with colorful names, while the Robot responded with dry comments, warnings, and mechanical loyalty. Their banter became one of the show’s main comic elements. Although Dr. Smith began as a villainous saboteur, he gradually became more of a comic troublemaker, and his scenes with the Robot helped shape the show’s lighter tone in later episodes.

The Robot’s design also reflected the public’s fascination with space-age technology during the 1960s. This was the era of the Space Race, when rockets, satellites, moon missions, computers, and robots captured the public imagination. Robot B-9 fit that world perfectly. It looked futuristic, but still had enough personality to feel approachable for a family audience. The character could be a helper, guardian, comic partner, or warning system depending on the scene.

Although Lost in Space originally ran for only three seasons, from 1965 to 1968, the Robot remained one of its lasting icons. The character appeared in later revivals, merchandise, model kits, toys, and fan collections. Even people who have not watched many full episodes often recognize the domed head, flexible arms, rolling base, and famous warning to Will Robinson.

The answer is Robot B-9. On Lost in Space, the character was often called simply The Robot, but Robot B-9 is the commonly used identification for the machine that protected the Robinson family aboard the Jupiter 2 and became famous for warning Will Robinson of danger.