Attack of the Giant Leeches is an independently made 1959 black-and-white science fiction-horror film, produced by Gene Corman and directed by Bernard L. Kowalski. It stars Ken Clark, Yvette Vickers and Jan Shepard. The screenplay was written by Leo Gordon. The film was released by American International Pictures on a double bill with A Bucket of Blood. Later, in some areas in 1960, Leeches played on a double bill with the Roger Corman film House of Usher.

Attack of the Giant Leeches was one of a spate of “creature features” produced during the 1950s in response to cold war fears; a character in the film speculates that the leeches have been mutated to giant size by atomic radiation from nearby Cape Canaveral.

Plot
In the Florida Everglades, a pair of larger-than-human, intelligent leeches live in an underwater cave. They begin dragging locals down to their cave, where they slowly feed on them, draining their victims of blood. Two of the first victims of the leeches are local vixen Liz Walker (Vickers), who has been cheating on her husband (Bruno VeSota), and Liz’s latest paramour. Game warden Steve Benton (Clark) sets out to investigate their disappearance. Aided by his girlfriend, Nan Grayson (Sheppard), and her father, Doc Grayson, Benton discovers the leeches’ underwater cavern. The creatures are destroyed when Steve, Doc and several state troopers blow up their underwater cavern using dynamite.

Cast
Ken Clark as Steve Benton
Yvette Vickers as Liz Walker
Jan Shepard as Nan Greyson
Michael Emmet as Cal Moulton
Tyler McVey as Doc Greyson
Bruno VeSota as Dave Walker
Gene Roth as Sheriff Kovis
Dan White as Porky Reed
George Cisar as Lem Sawyer
Joseph Hamilton as Old Sam Peters
Walter Kelley as Mike
Guy Buccola as Giant Leech
Ross Sturlin as Giant Leech