The Oregon Rex was one of several breeds of domestic cat with the rex mutation, which in the mid-20th-century occurred from spontaneous genetic mutation.After its acknowledgment as a separate breed, it enjoyed a short time of popularity among cat breeders in the United States. By now, due to crossbreeding with other Rex types, this breed seems to have merged with the other more popular Rex breeds like Devon Rex or Cornish Rex.
According to some claims, the first litters of typically Oregon-Rex-like cats occurred in 1944. The first documented case of an Oregon Rex cat is traced back to a litter of cats in the U.S. state of Oregon in 1955. The specific kitten differed from its siblings and its mother by having a curly coat whereas the others all had straight fur.At the same time, the first Cornish Rex were imported to the U.S. from Great Britain, and were soon interbred with the developing Oregon Rex breed. Breeders from Oregon then established a purebred Oregon Rex which soon became one of America's most popular Rex breeds. In the course of breeding, however, all types of Rex cats—each of which differ genetically—were crossbred, and the Oregon Rex did not endure as a stand-alone breed. The last purebred Oregon Rex cat is reported to have died in 1972.