Lost in Space Wally Cox, Grant Sullivan, Norman Leavitt, Tommy Farrell, Mercedes McCambridge, Lyle Waggoner, Albert Salmi, Royal Dano, Strother Martin, Michael J. Pollard, Byron Morrow, Arte Johnson, Fritz Feld, John Carradine, Al Lewis, Hans Conried, Dennis Patrick, Michael Rennie, Daniel J. Travanti and Michael Conrad. Jonathan Harris, although a permanent cast member, was listed in the opening credits as "Special Guest Star" in every episode of "Lost in Space". Props and monsters were regularly recycled from other Irwin Allen shows. A sea monster outfit that had featured on Voyage to the Bottom of the Sea (TV series) might get a spray paint
Land of the Giants the part of Dan Ericson, credited his previous football, track and pole vaulting work for helping him with the stunts required. Elements of Allen's "Lost in Space" series recur in "Land of the Giants", notably the relationship between foolish, greedy, on-the-run bank robber Alexander B. Fitzhugh (Kurt Kasznar) and the young boy Barry Lockridge (Stefan Arngrim), paralleling the relationship on "Lost in Space" between Doctor Smith and the young Will Robinson. Also, for main cast billing, Kasznar was treated contractually in the same manner as Jonathan Harris had been on "Lost In Space": billed in last place on the opening