Phanzig: (while he has Dr. Smith in the cat's cradle noose) I'm as innocent as the day I was born. As gentle as the day is long, harmless, tender. A prince of virtue.
Dr. Smith: We're doomed! Doomed!
Maureen: Oh really, Dr. Smith! Can't you think of some other word? Doomed is so final!
Dr. Smith: The only other word I can think of is extinction.
Dr. Smith: Be careful, William. It would be dreadful if those buttons played the same tricks on you as they did on me.
Will: Buttons don't play tricks, Dr. Smith. You must have done something wrong.
Dr. Smith: Comet, comet, go away! Come again another day!
Dr. Smith: (talking to the SOS canister he has just released into space) Adieu, little spool.
In space you will roam. Dr. Smith is a prisoner, a long way from home.
Robot: Would you like me to cross my sensors for you, Dr. Smith?
Dr. Smith: I prefer to rely on the winds of chance, not superstition.
Prof. Robinson: According to Smith that's the result of an abnormal airlock.
Maj. West: More like abnormal Smith.
Robot: Dr. Smith! In times of emergency one may dispense with formal attire!
Composer John Williams updates the show theme entirely for a work with a much faster tempo. The opening title sequence is also changed, giving it a flashier appearance.
The third season sees the second redesign of the Robinsons' costumes.