Attack of the Giant Leeches is a low-budget 1959 science fiction film from American International Pictures. It was directed by Bernard L. Kowalski, produced by Gene Corman and the screenplay was written by Leo Gordon. The film is in black and white, and runs for 62 minutes. It was one of a spate of monster movies produced during the 1950s in response to cold war fears; in the film a character speculates that the leeches have been mutated to giant size by atomic radiation from nearby Cape Canaveral.

This film was also called Attack of the Blood Leeches, Demons of the Swamp, She Demons of the Swamp, and The Giant Leeches.

In the Florida Everglades, a pair of larger-than-human, intelligent leeches are living in an underwater cave. They begin dragging local people down to their cave where they hold them prisoner and slowly drain them of blood.
One of the first people to be so taken is the local vixen, Liz Walker, played by Yvette Vickers. After a couple of gratuitous displays of flesh and some running around on her husband (Bruno VeSota,) Liz finds herself a prisoner of the leeches along with her current paramour. Game warden Steve Benton (Ken Clark) sets out to investigate their disappearance. Aided by his girlfriend Nan Grayson (Jan Sheppard) and her father, Doc Grayson, he discovers the cavern.

The giant leeches are unrealistically portrayed by men in suits, but they do provide suitably disgusting scenes when attacking their victims.