Trivia

In the stock footage from Flash Gordon (1936), shown in this film, as Flash is telling The Clay People about his previous encounter with Emperor Ming, Ming is bald and Dale Arden has blond hair. In this sequel, Ming has "pasted on" hair and Dale is a brunette. It has been reported that Jean Rogers (Dale Arden) had many other film roles pending at that time (1938) that called for her to be a brunette.

Buster Crabbe (Flash Gordon), Charles Middleton (Ming the Merciless) and Frank Shannon (Dr. Alexis Zarkov) are the only actors to appear in all three "Flash Gordon" serials.

Much of the background music was originally used in Bride of Frankenstein (1935). Also, the song that played in the background during the sequence recapping the previous chapter's events was the theme for The Invisible Man (1933).

This was the final appearance of Jean Rogers as Dale Arden.

The serial debuted in March of 1938, just seven months before the infamous Orson Welles' "War of the Worlds" Halloween broadcast. To cash in on the controversy caused by the radio show, the studio edited the serial into a feature film, Mars Attacks the World (1938), and released it to theaters in November of that year.