Radar Patrol vs. Spy King is a 1949 12-chapter black-and-white spy film serial produced and distributed by Republic Pictures from an original, commissioned screenplay collaboratively written by Royal K. Cole, William Lively and Sol Shor.

John Baroda, a neo-Nazi and his alter ego, The Spy King and his aide Nitra, are part of a sabotaging team for a vast defense system of radar stations along the US borders.

Radar Defense Bureau operative Chris Calvert comes to the rescue of radar scientist, Joan Hughes, who has been kidnapped by Baroda's henchmen... Radar Patrol vs. Spy King was budgeted at $164,970 although the final negative cost was $164,632 (a $338, or 0.2%, under spend).

[1] The special effects were created by the Lydecker brothers.

Radar Patrol vs. Spy King's official release date is November 23, 1949, although this is actually the date the sixth chapter was made available to film exchanges.