ACA is the American Canine Assoc. and is the registry many commercial breeders (Puppymills) and bad byb's use to register dogs. The requirements for registering dogs with them are not very stringent, I don't believe they do any facility inspections like AKC. Essentially it's a worthless registry, IMO. Disreputable breeders will often promote their pups are registered, and then you find out they are ACA registered....so what?