Lost In Space aired on CBS for three seasons between 1965 and 1968. The show lasted 83 episodes (84 if you count the unaired pilot).
Season 1
No Place to Hide (Unaired Pilot)
The Reluctant Stowaway
The Derelict
Island in the Sky
There Were Giants in the Earth
The Hungry Sea
Welcome Stranger
My Friend, Mr. Nobody
Invaders From the Fifth Dimension
The Oasis
The Sky is Falling
Wish Upon a Star
The Raft
One of Our Dogs is Missing
Attack of the Monster Plants
Return From Outer Space
The Keeper: Part I
The Keeper: Part II
The Sky Pirate
Ghost in Space
War of the Robots
The Magic Mirror
The Challenge
The Space Trader
His Majesty Smith
The Space Croppers
All That Glitters
The Lost Civilization
A Change of Space
Follow the Leader
Season 2
Blast Off Into Space
Wild Adventure
The Ghost Planet
The Forbidden World
Space Circus
The Prisoners of Space
The Android Machine
The Deadly Games of Gamma 6
The Thief From Outer Space
Curse of Cousin Smith
West of Mars
A Visit to Hades
The Wreck of the Robot
The Dream Monster
The Golden Man
The Girl From the Green Dimension
The Questing Beast
The Toymaker
Mutiny in Space
The Space Vikings
Rocket to Earth
Cave of the Wizards
Treasure of the Lost Planet
Revolt of the Androids
The Colonists
Trip Through the Robot
The Phantom Family
The Mechanical Men
The Astral Traveler
The Galaxy Gift
Season 3
Condemned of Space
Visit to a Hostile Planet
Kidnapped in Space
Hunter’s Moon
The Space Primevals
The Space Destructors
The Haunted Lighthouse
Flight Into the Future
Collision of the Planets
The Space Creature
Deadliest of the Species
A Day at the Zoo
Two Weeks in Space
Castles in Space
The Anti-Matter Man
Target: Earth
Princess of Space
The Time Merchant
The Promised Planet
Fugitives in Space
Space Beauty
The Flaming Planet
The Great Vegetable Rebellion
Junkyard in Space