Close-ups of the giant shrews were filmed using hand puppets. The wider shots used dogs made up as the shrews.
Actor / co-producer Ken Curtis once commented that he had to force himself not to laugh during filming when the shrews attacked because they were basically just "dogs covered in shag carpet."
The man playing Dr. Baines is Gordon McLendon. He was the uncredited executive producer and financier of this and its companion feature The Giant Gila Monster (1959). He owned radio stations and a chain of theaters in Texas.
A sequel, Return of the Killer Shrews (2012), was produced in 2012, again starring James Best as Thorne Sherman. Bruce Davison took the role of Jerry. The film also starred John Schneider and Rick Hurst, Best's co-stars in The Dukes of Hazzard (1979). The length of time between the original film's release and the sequel's release (53 years) is one of the longest between film sequels in history.
Coon dogs were used to play the killer shrews.