Screenwriter Wallace MacDonald said in an interview that he dreamed up the film, complete with character names, plot ideas, costumes, etc., after he was sedated by nitrous oxide while undergoing dental work. When he awoke he went directly home, put everything down on paper, and brought it to producer Nat Levine at Mascot Pictures, who loved the idea and approved the production.

Seven robots built originally for Dancing Lady (1933) for a dance sequence were cut from the finished film, although photos of the scene survive. The robots later appeared in "The Phantom Empire" and the serial Captain Video, Master of the Stratosphere (1951).

The main role was meant for Ken Maynard, but he dropped out due to the low-budget policies of Mascot Pictures and producer Nat Levine.

There is an alternate, rarely seen, version of this film in which Gene Autry is absent from the last part of the film. The plot reaches the same conclusion. Reportedly, Autry was not available at first, due to other commitments. The scenes in question were later re-shot when he was available.

The city of Murania was built for less than $1200 including utilizing a colander as the dome of a building.

A critically acclaimed article, "The Phantom Empire: Blazing a Trail to the Autry Empire", was written by George Turner for the April 1994 issue of "American Cinematographer."

CHAPTER TITLES: 1. The Singing Cowboy; 2. The Thunder Riders; 3. The Lightning Chamber; 4. Phantom Broadcast; 5. Beneath the Earth; 6. Disaster From the Skies; 7. From Death to Life; 8. Jaws of Jeopardy; 9. Prisoners of the Ray; 10. The Rebellion; 11. A Queen in Chains; 12. The End of Murania.