The Field Dog Stud Book of Chicago Illinois USA registers all breeds of dogs-records registered names, breeding background, color, age, sex, documents ownership, duplicates lost registration certificates and enrolls litters. The Field Dog Stud Book is the oldest purebred dog registry in the United States. Its' records date back to 1874 and comprise several million dogs of all breeds.

The FDSB has registered Llewellin setters since 1902.

Only the dogs registered at the FDSB can be considered Llewellins

Registration of Llewellin's litter requires THE DNA TEST